JPH0350147B2 - - Google Patents

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention relates to an improvement of a hydraulic control circuit device, and is used in power shift transmissions of industrial vehicles, forklifts, etc. .

(Prior Art) As a prior art related to the present invention, there is Japanese Patent Application No. 187850/1987, which was previously proposed by the present applicant. This is a hydraulic system consisting of an oil pump, a regulator valve, an inching valve, a selector valve, a change valve, a modulator valve, and a clutch servo. A first oil passage leading from the selector valve to the change valve and also to the clutch servo, a third oil passage from the change valve to one side of the modulator valve, and between the inching valve and the selector valve. The fourth oil passage extends from the first oil passage to the other side of the modulator valve.

(Problems to be Solved by the Invention) However, it has been found that the following problems occur in the above-mentioned prior art. That is, the fourth oil passage 32'
Since this is always input to one end of the modulator valve, there is a problem that the amount of oil consumed by the modulator valve increases. Furthermore, since the input oil path to the modulator valve via the change valve 50 is only the third oil path 34, the hydraulic surge generated due to a change in the select position of the select lever becomes large, and the shift shock becomes large. There is a problem with becoming. The technical objective of the present invention is to solve the above problems.

[Structure of the invention]

(Means for solving the problem) The technical means taken to achieve the above technical problem is to connect the first oil passage between the inching valve and the selector valve, one end of which is a line pressure oil passage. and the other end is connected to an intermediate port formed at an intermediate position of the modulator valve, and the intermediate port is formed at another intermediate position of the modulator valve in response to movement of the spool of the modulator valve. The input oil passage from the selector valve to the modulator valve passes through the second oil passage and the change valve, and the third oil passage connects to one side of the modulator valve. and a fifth oil passage branching from the third oil passage and reaching the other side of the modulator valve, and an orifice on one side or the other side of the modulator valve.

(Function) With the above technical means, the modulator valve is adjusted and the pressure of the fourth oil passage is regulated using the supply pressure from the third and fifth oil passages via the change valve, so the select position of the selector valve and There is no pressure loss due to change valve resistance. Therefore, the pressure supplied to the clutch servo is regulated by the modulator valve.

(Example) The present invention will be explained below based on examples.

FIG. 1 shows a flowchart of an embodiment of the hydraulic system of the present invention. That is, oil pump → regulator valve → inching valve → each clutch F-
In the oil passage configured as a C/L, R-C/L servo, the oil passage is further connected to the selector valve → change valve → modulator valve (one side and the other side). Further, an oil passage is connected from an oil passage between the inching valve and the selector valve to the modulator valve (intermediate side).

FIG. 2 shows the detailed hydraulic circuit of this embodiment. An oil pump 1 serving as a hydraulic pressure source is rotated by an engine output shaft (not shown). oil pump 1
The discharge port is connected to the input port b of the regulator valve 10 via a line 30, which is part of the first oil path, and is branched off and connected to the torque converter T/C via the orifice 4, and is further connected to the torque converter T/C through the orifice 4. It is supplied as oil to the lubricating part of the clutch.

The output port a of the regulator valve 10 is the first
It is connected to the port f of the inching valve 20 via a line 31 which is another part of the oil passage, and its output port g is connected to the line 3 which is another part of the first oil passage.
2 to the input port c of the selector valve 40. Each output port d, d of the selector valve 40 is connected to a respective clutch R-C/L, F-C/L.
It is connected to the servo via lines 33, 33' which are second oil passages, and is also connected to each input port a, b of the change valve 50.

The output port c of the change valve 50 is connected to the modulator valve 6 via a line 34 which is a third oil passage.
0 to one side input port f, and the fifth
It is input to the input port a on the other side via a line 34' which is an oil path. The line 32 is input to the intermediate input port b of the modulator valve 60 via a branch line 32' which is a fourth oil passage. Drained oil from each port c, d, e of the modulator valve 60 returns to the oil pan 2 via a line 35. On the other hand, the drained oil from the discharge ports a and e of the selector valve 40 returns to the oil pan 2 via the line 35'.

Drain oil from the regulator valve 10 is at ports c and d.
From there, it returns to oil pan 2 via line 35.

The regulator valve 10 itself may be of a known type, and the spool 11 is formed by balancing the urging force of the spring 15 with the input pressure acting on the lands 12, 13, 14 in opposition to this, that is, the pressing force due to pressure regulation. Pressure regulation is performed by changing the degree of opening of the oil chamber 16 and the land 12.

The selector valve 40 is a known one, and selectively connects or closes the input port c to the output ports b and d by switching the forward direction F and the backward direction R of a spool 41 having two lands 41a and 41b.

The change valve 50 selectively supplies one of its outputs to the modulator valve 60 in response to switching of the selector valve 40 between forward F and backward R.

The modulator valve 60 may be a known one,
A spool 61 presses against a piston 62 having a land 61a with a spring 63 interposed therebetween; a second piston 64 having an orifice 64a and biased leftward by a spring 65 (controls ports e and f); ). Modulator valve 6
0 moderates the degree of change in the output pressure of the inching valve 20, that is, the clutch pressure applied to the servo of each clutch F-C/L, R-C/L.

One of the clutches F-C/L and R-C/L is engaged and the other is released depending on the F and R positions of the selector valve, respectively. In the N position both are released.

The inching valve 20 has an inching spool 21 provided with lands 21a, 21b, and 21c that are biased in opposite directions by first and second springs 23 and 24 in a cylinder and control input pressure. An inching rod 22 is also disposed coaxially within the cylinder and presses the inching spool 21 via a first spring 23.
is operated in the direction of arrow A in conjunction with a pedal (not shown, such as an inching pedal or a brake pedal). Inching rod 22 is land 22
a, 22b, and supplies the input pressure from the line 32 to the oil chamber 25 through ports a, b, and i when it is not in operation (the lower half of Fig. 2 20), and when it is in operation (the upper half of Fig. 2). In the half part), port a is first closed, and then when the stroke is further made, discharge port c is opened and oil chamber 25 is opened.
Cuts off and releases the input pressure to. In order to ensure this kind of operation, the length between port a and port c (the shortest length of the inner edge part) L1 and land 2
The relationship between L2 and the length between 2a and 22b (the shortest length of the edge portion) is L1>L2. Preferably, when L1-L2=l, l is set to 0.5 to 1.0 mm.

The spool 21 forms an oil chamber 26 between a land 21a and a land 21b, and the land 21a restricts the input port f to a direction in which it is closed when the pedal is operated. The land 21b of the spool 21 closes the discharge port h when it is not in operation, and opens when it is in operation.

The discharge port d constantly communicates the housing chamber of the spring 23 with the discharge line 35.

Ports a, e, and g communicate with line 32 via constricted portions 28a, 28e, and 28g, respectively.

The operation of this inching valve 20 will be explained below. The state when the pedal is not depressed (non-actuated) is shown in the lower half of FIG. Exit to line 32. The line 32 enters the oil chamber 25 through ports a, b, and i, and together with the spring 24 pushes the spool 21 to the left. Also from line 32 to port e
Push the spool 21 to the right through the .

However, since the leftward pressing force is large, Fig. 2
The state of the lower half of 0 is maintained, and the discharge port h is closed. Therefore, the input pressure from the regulator valve 10 is the orifice 2 after the inching valve 20.
8a, 28e, and 28g are maintained in the line 32, enter the selector valve 40, and the line 3
2' to port b at the left end of modulator valve 60 to regulate the pressure in line 32.
This adjusted pressure is transmitted through lines 33 and 33' to F-
Since it enters the C/L and R-C/L servos, the pressure loss at the change valve 50 is not taken into consideration.

When you begin to press the pedal, the inching rod 22 begins to move in the direction of arrow A, and the inching rod 22 begins to move in the direction of arrow A.
leading to the closure. When the pedal is further depressed, the exhaust port c opens to release the pressure. Therefore, the pressure in the oil chamber 25 becomes a pressure corresponding to the difference in repulsive force between the spring 23 and the spring 24, and the spool 21 moves gently to the right in response to the opening of the discharge port c, as shown in FIG. 20. Shifts to the position shown in the upper half of the figure, the pressure in the line 32 decreases, and the F-C/
L, R-C/L is released.

The feature of the present invention is that the fourth oil passage 32'
A first oil passage 32 between the inching valve 20 and the selector valve 40, one end of which is a line pressure oil passage.
while the other end is connected to the modulator valve 6.
It is connected to the intermediate port b formed at the intermediate position of 0. The intermediate port b is arranged to be able to communicate with the drain port c formed at another intermediate position of the modulator valve by movement of the spool 61 of the modulator valve.

Next, the operation based on the above configuration will be explained. In FIG. 2, when the select valve is shifted to the forward F or reverse R position, the third and fifth oil passages 34,
Hydraulic pressure is generated at 34' via the change valve 50. Here, since the orifice 64a is provided on one side of the modulator valve 60, the pressure at port a is increased, and the force pushing the spool 61 to the right exceeds the force pushing the piston 62 to the left.
Therefore, the spool 61 moves to the right, but since the intermediate port b and the drain port c communicate with each other, the line pressures of the first to fifth oil passages decrease.
As a result, the pressure at port a decreases and spool 6
1 is held at a position where the pressure at port a and the load force acting on the spring 63 are balanced. after that,
Since the space between the pistons 62 and 64 is filled with oil via the orifice 64a, the force pushing the piston 62 to the left exceeds the acting load of the spring 63, which is equal to the force pushing the spool 61 to the right. is moved to the left. and,
The piston 62 directly contacts the spool 61 and presses the spool 61 to the left, thereby blocking the intermediate port b and the drain port c. Therefore, the line pressures of the first to fifth oil passages become the same as the oil pressure regulated by the regulator valve 10.

Therefore, the flow rate of the modulator valve 60 is regulated by the orifice 64a at the time of starting.
The starting shock can be alleviated by reducing the clutch capacity in order to engage the clutch servo without generating a pressure higher than the set pressure in a short period of time. Furthermore, since the fourth oil passage 32' is directly connected to the first oil passages 30, 31, and 32, which are line pressure oil passages, when the gradual increase in clutch servo pressure is completed, the amount of oil consumed by the modulator valve 60 can be reduced. This can be significantly reduced.

〔Effect of the invention〕

The present invention produces the following unique effects. That is,
Since only the fourth oil passage is directly connected to the line pressure oil passage, the amount of oil consumed by the modulator valve can be significantly reduced. Furthermore, the modulator valve generates a surge pressure higher than the set pressure in a short period of time due to the flow rate being regulated by the orifice during gear shifting.
This surge pressure shortens the operational response time for engaging the clutch servo, and at the same time, the surge pressure disappears when the gear shift is completed, making it possible to relieve the engagement shock.

[Brief explanation of drawings]

FIG. 1 is a flow chart of the present invention, and FIG. 2 is a hydraulic circuit diagram showing an embodiment of the present invention. 10... Regulator valve, 20... Inching valve, 30, 31, 32... First oil path, 3
2'...Fourth oil path, 33, 33'...Second oil path, 3
4...Third oilway, 34'...Fifth oilway, 40...
Selector valve, 50...Change valve, 60
...Modulator valve.

Claims (1)

[Claims] 1. Oil pump, regulator valve, inching valve, selector valve, change valve,
A first oil passage consisting of a modulator valve and a clutch servo, which runs from the oil pump to the selector valve via the regulator valve and inching valve, and from the selector valve to the change valve and to the clutch servo. In a hydraulic system having a second oil passage, one end is connected to a first oil passage between the inching valve and the selector valve, which is a line pressure oil passage, and the other end is located at an intermediate position between the modulator valve. a fourth oil that is connected to an intermediate port formed in the modulator valve, and that intermediate port can communicate with a drain port formed in another intermediate position of the modulator valve in response to movement of the spool of the modulator valve; An input oil passage from the selector valve to the modulator valve passes through the second oil passage and the change valve, and a third oil passage and the third oil passage connect to one side of the modulator valve. A hydraulic device comprising: a fifth oil passage branching from the passageway and reaching the other side of the modulator valve; and an orifice on one side or the other side of the modulator valve.