JPS6059457B2 - Inching valve mechanism - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in inching valve mechanisms.

A conventional inching valve mechanism is constructed as shown in Fig. 1. In Fig. 1, 1 is a pump that is a source of hydraulic pressure, and is driven by an engine output shaft (shown) to pump oil from an oil tank 2. Suction and discharge pressure oil to the pipe line 3.

After the oil in the pipe line 3 is regulated to a constant pressure (line pressure) by the regulator valve 34, the excess oil is transferred to the torque converter'.
Flows to Γ and C. The conduit 3 also branches into a conduit 4, which communicates with a port 10 of an inching valve mechanism 5, which will be described below. Fitting hole 7 of valve body 6 of inching valve mechanism 5
has ports 8, 9, 10, and 12; port 8
, 12 communicate with the oil tank 2, the port 10 communicates with the pipe line 4, and the port 9 communicates with the pipe line 30.

A spool 13 is slidably inserted into the insertion hole, and an annular groove 14 is formed on the outer periphery of the spool 13.A cylindrical hole 16 is formed at the right end of the spool 13. A shoulder portion 17 is formed at the left end, and a piston 18 is slidably inserted into the hole 16, and the right end surface of the piston 18 is attached to a cover 19 attached to the right end portion of the insertion hole 7. Further, the cylindrical hole 16 communicates with the annular groove 14 via an oil filler 20. A spool 22 is also slidably inserted into the insertion hole 7, and the spool 22 is slidably inserted into the insertion hole 7. A small diameter land 23 is formed at the right end of the spool 22, and a pressure regulating spring 24 is interposed between it and the shoulder 17 of the spool 13.The left end of the spool 22 is connected to the lower end of the inching pedal 26. A cover 29, which functions as a stopper, is attached to the left end of the insertion hole 7 to prevent the spool 22 from slipping out of the valve body 6 when the inching pedal 26 is depressed. A return spring 28 is attached to the inching pedal 26, and its urging force constantly pushes the spool 22 to the right, causing the small diameter land 23 and the shoulder 17 of the spool 13 to come into contact with each other.Inching valve The boat 9 of the mechanism 5 communicates with a forward/reverse switching valve 31 via a conduit 30, and this switching valve 31 functions to supply oil to a forward clutch 32 or a reverse clutch 33 (not shown) of the vehicle to move the vehicle forward. Or put it in the reverse state.By operating the inching pedal 26, the action described below occurs, and it becomes possible to temporarily put the vehicle in neutral, or put it in a so-called half-clutch state and make slight movements of the vehicle.Inching pedal 2
In the solid line position shown in the figure where the spool 6 is not depressed, both the spools 13 and 22 come into contact with the right end due to the return spring 28, and the oil under the line pressure of the pipe 4 passes through the boat 10, the annular groove 14, and the oil hole 20 into the cylindrical hole. 16 to generate a force that pushes the spool 13 to the left, but the force exerted by the return spring 28 is greater, so it maintains the state in the illustrated position.

Therefore, the oil in the port 10 flows through the boat 9 to the pipe line 30 without being depressurized, and an oil pressure equal to the line pressure of the pipe line 4 is generated in the pipe line 30. This corresponds to the hydraulic pressure P1 in FIG. 2 (hereinafter this hydraulic pressure will be referred to as clutch hydraulic pressure).Next, the inching pedal 26 is depressed in the direction of the broken line in the figure, and the small diameter land 23 of the spool 22 and the shoulder of the spool 13 17 separates and spools. Even if 13 becomes slidable,
The boat 10 is closed by the spool 13 and the annular groove 1
The clutch oil pressure in line 30 maintains a value equal to the line pressure in line 4 until boat 8 is released via line 4.
This corresponds to the period up to stroke S1 in FIG.
When the inching pedal 26 is further depressed and the stroke of the spool 22 reaches S1, the boat 10 can be closed by the spool 13 and the boat 8 can be opened by the annular groove 14. The oil pressure is reduced and regulated to maintain P2 in FIG. As the inching pedal 26 is further depressed and the stroke of the spool 22 increases, the load on the pressure regulating spring 24 decreases, and the clutch hydraulic pressure in the conduit 30 decreases accordingly.
The range of strokes S1 to S2 in FIG. 2 corresponds to this. When the inching pedal 26 is further depressed, the pressure regulating spring 24
becomes a free length and its load becomes zero, so the clutch oil pressure of the pipe line 30 becomes zero, and S2 to S3 in FIG. 21 correspond to this. As described above, the clutch oil pressure in the conduit 30 changes depending on the amount of depression of the inching pedal 26, and the engagement state of the forward clutch 32 or reverse clutch 33 of the vehicle is continuously and uniformly changed from fully engaged to fully disengaged. By changing this, it is possible to move the vehicle at very slow speeds or to stop it in a neutral position.

The piston 18 receives hydraulic pressure (pipe 3
It is inserted to adjust the force caused by the clutch oil pressure (equal to zero clutch oil pressure), but it also makes the sliding of the spool 13 smoother.
In order to ensure the change in clutch oil pressure, it cannot be selected too small.

Furthermore, when the inching pedal 26 is not operated, oil at line pressure P1 flows into the cylindrical hole 16, and the load of the return spring 28 must be installed with enough strength to overcome this hydraulic pressure. As the inching pedal becomes larger, the inching pedal operating force also becomes heavier, and the lever ratio of the link mechanism must be increased in order to make the inching pedal lighter in terms of operability.
Then, the pedal stroke will inevitably become larger,
The drawback was that the inching peggle was difficult to operate.
The present invention was proposed for the purpose of eliminating the drawbacks of the conventional inching valve mechanism described above. The valve body has boats arranged at appropriate intervals on the inner peripheral wall at appropriate intervals along the axial direction. a first spool having an annular groove in the valve body; a second spool that is slidably inserted into the other side of the valve body and has an adjustment spring interposed between the first spool and the second spool; An inching pedal is connected to the extending end by a pin and is always rotated counterclockwise by a return spring so as to urge the second spool to always come into contact with the inner end of the first spool. In the inching valve mechanism, a boat communicating with a branch pipe from a pipe leading to the forward/reverse switching valve and a boat communicating with an oil tank are disposed at appropriate locations on the inner circumferential wall of the valve body, and a boat communicating with the oil tank is disposed at a suitable location on the inner circumferential wall of the valve body, and A sliding member having an oil passage that can communicate with the boat leading to the boat, one side of which can come into contact with the second spool, and the other side forming a pressure receiving chamber that communicates with a hydraulic pressure source or an oil tank via the oil passage. When the inching pedal is operated, the pressure oil from the hydraulic pressure generation source is introduced into the pressure receiving chamber, and when the inching pedal is not operated, the introduction of the pressure oil from the hydraulic pressure generation source is cut off. The present invention relates to an inching valve mechanism characterized in that it is configured so as to.

The present invention will be specifically explained below with reference to embodiments shown in FIGS. 3 and 4.

The present invention is characterized by a configuration in which the conventional inching valve mechanism shown in FIGS. 1 and 2 is partially modified as will be described later, and each of the conventional inching valve mechanisms is The codes of the members corresponding to the members are as follows:
1 and 2, all numbers are indicated by adding 100 to the reference numbers of the members shown in FIGS. 1 and 2. As shown in FIG. 3, boats 111 and 115 are added to the fitting hole 107 of the valve body 106 in addition to the boats of the conventional example shown in FIG.
The conventional example includes an oil hole 120, a cylindrical hole 116, and an annular groove 1.
In addition to 14, there are a fitting hole 136, a boat 121, an oil hole 138,
An annular groove 139 is formed, and a sliding member 132 is slidably inserted into the insertion hole 136 to form a pressure receiving chamber 140 between the piston 118 in the cylindrical hole 116 and the sliding member 132. Oil holes 133 and 134 and a shoulder 137 are formed in the sliding member 132, and the piston 118 and the sliding member 132
A return spring 125 is interposed between them.

Small diameter lands 123 and 135 are formed on the second spool 122, and the first spool 113 and the sliding member 132, respectively, have small diameter lands 123 and 135.
The movement of the sliding member 132 is restricted by both the return spring 125 and the second spool 122. A pressure regulating spring 124 is interposed between the second spool 122 and the first spool 113, and a pipe line 130a branched from the pipe line 130 communicates with the boat 111.
is in communication with the oil tank 102. Each member other than the parts described above has almost the same structure as the conventional example shown in FIG. One embodiment of the present invention is configured as described above,
As shown in FIG. 3, in the illustrated position where the inching pedal 126 is not depressed, the oil in the pipe 104 flows from the boat 110, the annular groove 114 of the first spool 113, and the boat 109 to the pipe 130 without being depressurized. , a hydraulic pressure equal to the line pressure in line 104 is generated in line 130.

The oil in the pipe 104 flows to the boat 121 through the oil hole 120, but since the sliding member 132 is moved to the right by the second spool 122, the oil in the oil hole 133 and the boat 1
21 is in a closed state, and similarly branch pipe 130a
However, since the annular groove 139 of the first spool 113 closes the boat 111, the oil of the boats 121 and 111 does not flow into the pressure receiving chamber 140, respectively.

On the other hand, since the annular groove 139 opens the boat 115,
The pressure receiving chamber 140 is in communication with the oil tank 102 via the oil hole 138, and no hydraulic pressure is generated in the pressure receiving chamber 140. As a result, the force that attempts to move the first spool 113 to the left is only the load of the return spring 125. next,
Depress the inching peggle 126, and the second spool 122
When the amount of leftward movement of the second spool 122 becomes larger than the stroke S1 in FIG.
5 and the end of the sliding member 132 are separated, and the sliding member 132 is moved so that the shoulder portion 137 is moved to the first spool 1 by the return spring 125.
13 until it comes into contact with the end of the cylindrical hole 116 and moves to the left.

As a result, the boat 121 of the first spool 113 and the oil hole 133 of the sliding member 132 communicate with each other, and the oil in the boat 111 flows through the oil hole 120, boat 121, seventh oil hole 133, 134, and flows into the pressure receiving chamber 140. . On the other hand, the pressure receiving chamber 140 communicates with the oil tank 102 via the oil hole 138, but since the diameter of the oil hole 138 is smaller than the diameter of the oil hole 120,
The amount of oil flowing in through the oil hole 120 and the amount of oil flowing in through the oil hole 13
Oil pressure is generated in the pressure receiving chamber 140 due to the amount of oil flowing out through the spool, and this force causes the first spool 113 to move to the left. As the first spool 113 moves, the annular groove 139 closes the boat 115 and opens the boat 111, so the flow from the oil hole 138 to the oil tank 102 is eliminated.
Conversely, oil flows in from the branch pipe 130a. When the first spool 113 moves further to the left while oil flows into the pressure receiving chamber 140 from both the oil hole 120 and the oil hole 138, the state shown in FIG. 4 is reached, and the oil pressure in the boat 109 and the pipes 130, 130a is reduced. A constant clutch oil pressure is maintained, and the same pressure reduction effect as in the conventional example is performed. The effect when the inching pedal 126 is further depressed is exactly the same as the conventional example, and by changing the mounting load of the pressure regulating spring 124,
As shown in the strokes S1 to S3 in Fig. 2, the pipe line 13
0 clutch oil pressure changes. Also, when the amount of depression of the inching pedal 126 is decreased, the spool 122
Until the small diameter land 135 comes into contact with the end of the second piston 132, the operation is the same as that of the conventional example.

When the small diameter land 135 comes into contact with the sliding member 132, the sliding member 132 moves to the left, and the boat 121 of the first spool 113 and the oil hole 133 of the sliding member 132 are closed. Although oil no longer flows from the boat 120 to the pressure receiving chamber 140, the oil in the pipe 130 continues to flow through the oil hole 138, so the oil pressure in the pressure receiving chamber 140 is maintained, and the mounting load of the pressure regulating spring 124 Perform appropriate depressurization. Then, as the amount of depression of the inching pedal 126 is further reduced, the small diameter land 12 of the second spool 122
3 and the end of the first spool 113 come into contact with each other, and in order to move the first spool 113 to the right, the annular groove 114
8 and open the boat 110 to stop the decompression action.

Furthermore, in the annular groove 139. Even if the boat 111 is closed and the boat 115 is opened, the oil in the pressure receiving chamber 140 is discharged into the oil tank 102 through the oil hole 138, and the initial installation state is restored.
The inching valve mechanism of the present invention has the above configuration,
This invention because it has an action! According to the above, the mounting load of the return spring 125 in the pressure receiving chamber 140 may be sufficiently small as it only requires a force to overcome the sliding resistance of the sliding member 132. The load may be as small as the clutch oil pressure P2, that is, the sum of the maximum mounting load of the pressure regulating spring 124 and the return spring 125. Therefore, compared to the case where a force that overcomes the clutch oil pressure P1 is required in the conventional example, the load on the return spring 128 can be made sufficiently small, and the pedal stroke is also inevitably reduced, improving its operability. This can have a practical effect of improving the condition. Next, a second embodiment is shown in FIG. 5, which differs only in the structure of the pressure receiving chamber 140 compared to the first embodiment. Each member is shown below.

Spring 23 returning to cylindrical hole 216 of first spool 213
9 only, and the valve body 206 right end cover 219 is)
It is attached to the valve body 206 so that the oil is completely sealed, and the pressure receiving chamber 24 is surrounded by the cover 219, the insertion hole 207 of the valve body 206, and the first spool 213.
0, and the other parts have exactly the same structure as the first embodiment. In this embodiment, since the area of the pressure receiving chamber 240 is larger than that of the pressure receiving chamber 140 of the first embodiment, the mounting load of the pressure regulating spring 224 becomes large, and as a result, the load of the pedal part return spring 228 also becomes large. Depending on the requirements of the vehicle to which the clutch is applied, there are cases where the clutch oil pressure P2 at stroke S1 in FIG. There is.

As a result, according to this embodiment, it is possible to appropriately select a good relationship between the pedal operation and the stroke.
This embodiment has the advantage that it can be constructed with a simpler structure than the embodiments.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a conventional inching valve mechanism, FIG. 2 is a graph showing the relationship between clutch oil pressure and spool stroke due to the operation of the inching pedal, and FIG.
4 and 4 are longitudinal sectional views schematically explaining one embodiment of the present invention, FIG. 3 shows the state when the inching pedal is not operated, and FIG. 4 shows the state when the inching pedal is being operated. The explanatory diagram, FIG. 5, is an explanatory diagram corresponding to FIG. 3 of another embodiment of the present invention. In FIGS. 3 to 5, 102: oil tank, 104
: Pipe line from hydraulic pressure source, 105: Inching valve mechanism, 106: Valve body, 107: Fitting hole, 108, 109
, 110, 111, 112, 115: Boat on inner peripheral wall of valve body 106, 113: Cylindrical hole 116, oil hole 20, boat 121, insertion hole 136, oil hole 138, annular groove 139
a first spool, 122; a second spool, 124;
: Pressure adjustment spring, 125: Return spring, 126: Inching pedal, 128: Return spring, 130: Pipe line to forward/reverse switching valve, 130a: Branch pipe line, 132: Oil line 133
, 134; 140: pressure receiving chamber;

Claims (1)

[Claims] 1. A valve body having a port connected to a hydraulic pressure source, a port connected to a forward/reverse switching valve, and a port connected to an oil tank at appropriate positions on the inner circumferential wall at appropriate intervals along its axial direction; is slidably inserted into one side of the valve body,
The first part has a cylindrical hole on the outer side and an annular groove on the outer periphery.
a spool, a second spool that is slidably inserted into the other side of the valve body and has an adjustment spring interposed between it and the first spool; a pin is connected to the extending end of the second spool; It is always rotated counterclockwise by the return spring, and
In an inching valve mechanism comprising an inching pedal that is biased so that the spool always comes into contact with the inner end of the first spool, a conduit leading to the forward/reverse switching valve is installed at an appropriate location on the inner circumferential wall of the valve body. A port that communicates with a branch pipe from the oil tank and a port that communicates with the oil tank are provided, and an oil passage that communicates with the port that communicates with the forward/reverse switching valve is provided, and one side is capable of contacting the second spool. ,
The other side is equipped with a sliding member that forms a pressure receiving chamber that communicates with a hydraulic pressure source or an oil tank via an oil passage, and when the inching pedal is operated, the pressure of the hydraulic pressure source flows into the pressure receiving chamber. An inching valve mechanism characterized in that the inching valve mechanism is configured such that when the inching pedal is not operated, the introduction of pressure oil from a hydraulic pressure generating source is cut off.