JPH0336141B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an accelerator valve suitable for use in vehicles, particularly construction vehicles such as crane trucks.

When the driver of a construction vehicle such as a crane truck leaves his seat and attempts to ground the vehicle's equipment, such as an outrigger, from the outside, the engine speed is increased slightly and the discharge volume of the hydraulic pump is increased in order to do the work as quickly as possible. It is necessary to maintain a large amount of For this purpose, the accelerator valve is kept in its operating state. With conventional accelerator valves, after stepping on the accelerator pedal, the hand valve that is connected to the exhaust port of the accelerator valve is shut off, which allows the hand valve connected to the exhaust port of the accelerator valve to be connected to the exhaust port of the accelerator valve even if the foot is released from the accelerator pedal. The air in the actuator that controls engine rotation is not discharged, and the discharge system is air-locked.

In such a conventional accelerator valve,
When air leaks occur within the exhaust port system or the discharge port system, the air pressure that maintains the actuator in its operating state decreases, causing a problem in that the desired rotational state of the engine cannot be maintained.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an accelerator valve that can maintain a desired engine rotational state even if air leaks occur within the exhaust port system or the discharge port system. This object is achieved according to the invention by providing a valve body having an inlet connected to a source of fluid pressure, an outlet connected to a fluid-pressure-operated device, and an outlet; A supply/discharge valve that opens and closes communication between the outlet and the exhaust port, a piston that is slidably inserted into a cylinder hole provided in the valve body and can operate the supply/discharge valve, and a piston located at the top of the valve body. In an accelerator valve, the accelerator valve includes a plunger that is driven by a swingably mounted accelerator pedal and presses the piston, wherein a plurality of engagement members are arranged on at least a portion of the outer periphery of the plunger and are aligned along the moving direction of the plunger. A locking device is provided in the valve body, the locking device having a notch and a locking piston actuated in response to a locking command signal and engageable in at least one of the engagement notches to hold the plunger in its operative position. This is achieved by an accelerator valve, which is installed.

Hereinafter, an accelerator valve according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, the entire accelerator valve is indicated by 1, and has a cylinder hole 3 consisting of a large-diameter hole 4, a medium-diameter hole 5, a small-diameter hole 6, and a valve hole 7 in order from the top of the valve body 2. . The lower opening of this cylinder hole 3 is closed by a lid member 8 fitted with a seal member 10. The lid member 8 includes a supply port 9, to which a compressed air source is connected via piping (not shown). In addition, the valve body 2 has an outlet port 1 in the lower part of the peripheral wall.
1. Has an exhaust port 12 in the upper part of the peripheral wall;
Operating equipment is connected to 1 via piping, although not shown. A cap 13 with a hole is screwed onto the exhaust port 12, and one end of an exhaust pipe 14 is inserted through the through hole of the cap 13 and fixed.

A stepped piston 15 is inserted into the large diameter hole 4, medium diameter hole 5, and small diameter hole 6 of the cylinder hole 3, and a bolt 17 is screwed into the tip of the small diameter portion 16. There is. Further, a spring receiving member 18 is slidably fitted into the circumferential surface of the tip of the small diameter portion 16, and a reaction force spring 19 is stretched between this and the large diameter portion 80 of the piston 15. A compensation spring 20 is further disposed inside the reaction force spring 19 and is supported on the middle diameter portion 21 of the piston 15 . The large diameter portion 80 of the piston 15 is fitted with a seal ring 22 and is slidable relative to the medium diameter hole 5 of the cylinder hole 3, and the lower end portion is fitted with a seal ring 26 and is slidable into the small diameter hole of the cylinder hole 3. It is slidable with respect to the portion 6.

An atmospheric pressure chamber 24 and a control pressure chamber 25 are defined within the cylinder hole 3 by the large diameter portion 80 of the piston 15, and a supply/discharge valve 27 is disposed within the valve hole portion 7. An inverted L-shaped passage 23 is bored through the piston 15, and the lower end 23a of this passage 23 is formed into a conical shape and serves as a valve seat for the supply/discharge valve 27. In the illustrated normal state, a valve chamber 28 is formed between the piston 15 and the lid member 8 in the valve hole 7.
and the atmospheric pressure chamber 25 are in communication via a passage 23.

The supply/discharge valve 27 includes a ball valve 29, a spring receiving member 30 on which it is mounted, a valve spring 32 stretched between this member 30 and the lid member 8, and a valve rod that contacts the ball valve 29 at its upper end. 33, the lower end 3 of this rod 33
In the normal illustrated state, the ball valve 29 is separated from the valve seat 23a, but the valve rubber 35 has a taper formed at the upper end of the supply port 9. It is in contact with the portion 36. That is, the tapered portion 36 functions as a valve seat for the valve rubber 35. The valve rod 33 is slidable into a small hole 37 formed at the upper end of the lid member 8 and communicating with the supply port 9. Further, a spring 31 for returning the piston 15 is stretched between the piston 15 and the lid member 8 on the outside of the valve spring 32.

A notch 38 is provided on one side of the lower end of the piston 15.
is formed, thereby facilitating the inflow of compressed air from the valve chamber 28 into the passage 23. Further, a through hole 39 serving as a passage is bored in the inner wall portion 2a forming the outlet port 11 in the valve body 2, so that the control pressure chamber 25 and the outlet port 11 are always in communication.

A lid body 41 is fixed above the valve body 2 so as to cover the upper opening of the cylinder hole 3. A plunger insertion opening 42 is formed approximately in the center of the lid 41, and a plunger 43 is slidably inserted through the opening 42. A rubber dustproof boot 44 is attached between the upper end of the peripheral wall of the plunger 43 and the upper surface of the lid 41 to prevent dust from entering the interior. A plurality of circumferential grooves 45 are formed in a part of the outer periphery of the plunger 43, as also shown in FIG. Also plunger 43
A hole 46 is formed inside the hole 46, into which the head of the bolt 17 mentioned above projects. plunger 43
is in contact with the circumferential surface of a roller 49 that is supported by a shaft 50 on an accelerator pedal 47 whose upper surface is covered with a rubber plate 48 . The accelerator pedal 47 is the lid body 4
The rotary shaft 52 is rotatably mounted on the lid body 41 by means of a rotary shaft 52 which is rotatably supported through a single bearing 51 . Bolt 53 is an adjustment bolt for adjusting the non-operating position of accelerator pedal 47, and 54 is a fixing nut.

Next, the locking device 55 provided in the right half of the lid 41 will be explained.

A cylinder hole 56 is bored in the right half of the lid 41, and a lock piston 57 having a T-shaped cross section is inserted into the cylinder hole 56.
is slidably inserted. lock piston 5
The large diameter portion 60 of No. 7 is fitted with a seal ring 58 to define a compressed air chamber and an atmospheric pressure chamber on both sides thereof. Also, the large diameter portion 60 and the partition wall portion 41a inside the lid body 41
A spring 59 is stretched between the two. The small diameter portion 61 of the lock piston 57 fits into a hole formed in the partition wall portion 41a, and a pawl 62 formed at the tip thereof.
is opposed to the groove 45 of the plunger 43 described above. Also, a small pin 64 is provided at the tip of the small diameter portion 61.
is fixed, and is engaged with a small groove 63 formed in the partition wall portion 41a. This prevents the lock piston 57 from rotating. On the other hand,
As shown in FIG. 2, a small screw 69 is screwed into a portion of the lid 41 and engages with a recess 70 formed in a portion of the outer periphery of the plunger 43. This prevents the plunger 43 from rotating.

A lid member 65 is screwed onto the open end of the cylinder hole 56, and a seal ring 67 seals between them. A passage 66 and a lock command signal input port 68 are formed in the lid member 65 in conjunction with the passage 66. By pressing the lock command button provided on the driver's seat, a certain amount of air pressure is piped into the lock command signal input port 68. It is now being supplied through. The bolt 40 screwed into the upper part of the peripheral wall of the valve body 2 functions as a piston stopper during assembly.

Although the embodiment of the present invention is configured as described above,
This effect will be explained below assuming that it is applied to a construction vehicle.

Now, when the driver depresses the accelerator pedal 47 to increase the engine speed, the plunger 43 is pushed down via the roller 49. As a result, the piston 15 is driven downward via the spring 19, and further via the compensation spring 20 when the stroke is large, and the ball valve 29 of the supply/discharge valve 27 is seated on the valve seat 23a at the lower end of the piston 15. The valve rod 33 is pushed down and the valve rubber 35 is pressed against the valve seat 36.
Leave the room. Therefore, communication between the valve chamber 28 and the atmospheric pressure chamber 24 is cut off, but the valve chamber 28 and the supply port 9 are kept in communication, and compressed air flows into the valve chamber 28 from the compressed air source. Compressed air is supplied from the pump through the outlet 11 to the actuator, which is a working device. On the other hand, the compressed air also flows into the control pressure chamber 25 through the passage 39 and enters the large diameter portion 80 of the piston 15.
is pressed against the spring force of the reaction springs 19 and 20. Therefore, when this pushing force increases to a value corresponding to the pushing force applied to the plunger 43 by the pedal 47, the piston 15 moves slightly upward, and the ball valve 29 remains seated on the valve seat 23a, but the valve The rubber 35 is seated on the valve seat 36, and the pressure in the control pressure chamber 25, that is, the pressure to the actuator connected to the outlet 11, is maintained at a constant value. When the driver determines that the desired engine speed has been achieved, he presses the lock command button.
Then, a predetermined air pressure is supplied to the lock command signal input port 68, and the lock piston 57 is pushed to the left in the figure against the spring force of the spring 59.
As a result, the pawl 62 formed at the tip of the lock piston 57 is now exposed to the opposing groove 4.
5 is engaged. Plunger 43 is reaction force spring 1
9 and 20 and the spring force of the return spring 31 of the piston 15, the pawl 62 of the lock piston 57 remains in the groove even if the driver takes his foot off the pedal 47. 45, the plunger 43 is held in this working position. Note that since the groove 45 is formed as a ratchet groove, it is possible to further push down the plunger 43 by depressing the pedal 47 in this state.
It cannot be moved upwards.

In the above-mentioned state, the driver can leave his seat and quickly ground the outriggers, for example, from the outside because the engine speed has reached a desired value.

When the lock command release button on the driver's seat is pressed after the work, the compressed air applied to the input port 68 is exhausted and the lock piston 57 returns to the right by the spring force of the spring 59. As a result, the pawl 62 of the lock piston 57 separates from the groove 45 and the plunger holding state is released. Plunger 43 and piston 15 return to the illustrated position under the force of springs 19, 20, 31. As a result, the ball valve 29
is removed from the valve seat 23a as shown in the figure, so the compressed air that has been applied to the actuator through the outlet 11 and the compressed air that has been applied to the control pressure chamber 25 is transferred to the passage 23, the atmospheric pressure chamber 24, the exhaust port 12 and the compressed air that has been applied to the control pressure chamber 25. The air is exhausted to the outside through the exhaust pipe 14.

In the above description, the lock command is released by pressing the release button on the driver's seat, but the invention is not limited to this, and the lock command may be released by pressing the brake pedal, for example.

In addition, in the above embodiment, the plurality of grooves 45 are formed only in a part of the outer periphery of the plunger 43, but the plunger 43 has a screw pin 69, a recess 70,
The rotation is stopped by the lock piston 57.
Since rotation is prevented by the pin 64 and the small groove 63, the pawl 62 of the lock piston 57 can accurately engage with one of the plurality of grooves 45.

Although the embodiments of the present invention have been described above, the present invention is of course not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the lock piston 57 is driven by pneumatic pressure, but instead of this, it may be driven electromagnetically.

Alternatively, a lock command release button may be provided at an appropriate position in the vehicle outside the driver's seat so that the engine speed is immediately reduced after the work is completed.

Further, in the above embodiment, the ratchet groove 45 is formed on the outer periphery of the plunger 43 as a notch for engaging the lock piston 57, but the shape of the groove is not limited to this. Alternatively, the plunger 43 may have multiple holes or slits in the vertical direction instead of grooves.
It may be formed on the outer periphery of the. In this case, it is necessary to change the shape of the claws of the lock piston 57, but it is also desirable to taper the openings on the lock piston side to facilitate engagement with holes and slits.

Further, although the above embodiments have been described in the case where the present invention is applied to a construction vehicle, the present invention is applicable to general vehicles.

As described above, according to the accelerator valve of the present invention, even if the pedal force is released, the plunger itself that drives the supply/discharge valve is locked in its operating state by the lock piston, so that the plunger itself that drives the supply/discharge valve is locked in its operating state by the lock piston. Even if an air leak occurs in the discharge system that connects the outlet and the actuator that controls the rotation of the engine and the pressure drops, this drop will be compensated and regulated by the original pressure from the air tank as the fluid pressure source, and the desired pressure will be maintained. It is possible to maintain the engine rotation state.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an accelerator valve according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the - line in FIG. In the figure, 1... accelerator valve, 2...
... Valve body, a = inner wall part, 3 ... cylinder hole, 9 ...
... Supply port, 11 ... Outlet port, 12 ... Exhaust port, 1
5...Stepped piston, 27...Supply/discharge valve, 43...
Plunger, 45... Groove, 47... Accelerator pedal, 55... Lock device, 57... Lock piston, 62... Pawl, 68... Lock command signal input port.

Claims (1)

[Claims] 1. A valve body having a supply port connected to a fluid pressure source, a discharge port connected to a fluid pressure operated device, and an exhaust port, and between the supply port and the discharge port and between the discharge port and the exhaust port. a supply and discharge valve that opens and closes communication with the valve body; a piston that is slidably inserted into a cylinder hole provided in the valve body and can operate the supply and discharge valve; and an accelerator pedal that is swingably attached to the upper part of the valve body. In the accelerator valve, the accelerator valve includes a plunger that is driven by a plunger and presses the piston, wherein a plurality of engagement notches are formed in at least a part of the outer periphery of the plunger and are aligned along a moving direction of the plunger, and a lock An accelerator valve comprising a locking device mounted on the valve body, the locking device being actuated in response to a command signal and having a locking piston engageable in at least one of the engagement notches to hold the plunger in its operative position.