JP2009008130A - Inching device of industrial vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inching device of an industrial vehicle capable of constantly preventing or suppressing noise and vibration due to collision of an inching spool with an inching valve even in different operating states of an inching pedal. <P>SOLUTION: The inching device is equipped with the inching pedal 11, the inching valve 30, and an inching cable 18. The inching valve 30 includes an inching rod 34 that slides in a valve cylinder 31, and the inching spool 41 whose position is regulated by fluid pressure in the valve cylinder 31. The inching rod 34 is divided into a cable side rod body 35 on the cable side in the axial direction, and a spool side rod body 36 on the inching spool 41 side. An elastic body 38 is interposed between the cable side rod body 35 and the spool side rod body 36. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inching device for an industrial vehicle, and more particularly to an inching device for an industrial vehicle provided with an inching valve operated by depressing an inching pedal.

  A forklift that performs cargo handling work is a type of industrial vehicle. For example, in a forklift equipped with a torque converter, the supply amount (pressure) of hydraulic oil to the clutch is finely controlled to keep the clutch in a so-called half-clutch state for a predetermined time. Thus, a clutch hydraulic control device is provided in order to improve the workability of cargo handling and to smoothly stop and start the vehicle.

FIG. 3 is a hydraulic circuit diagram showing a clutch hydraulic pressure control device 50 for a forklift equipped with a torque converter.
An oil pump 52 driven by an engine 51 mounted on the vehicle is configured to supply hydraulic oil to a regulator valve 53 and an inching valve 54, respectively.
The regulator valve 53 adjusts the pressure of the hydraulic oil to a predetermined pressure and supplies the hydraulic oil to the torque converter 55.
The hydraulic oil from the torque converter 55 is cooled by the oil cooler 56 and then sent to the wet forward clutch 57 and the reverse clutch 58.

The inching valve 54 controls the first inflow port 54 a through which the hydraulic oil from the oil pump 52 flows directly from the pipe and the hydraulic oil that flows in from the pipe branched from the pipe through the throttle valve and the accumulator 59. And a second inflow port 54b that flows in.
The inching valve 54 is provided with an inching rod (not shown) operated by the inching pedal 60, and a slidable inching spool (not shown) is provided in the inching rod.

The inching rod is displaced by the operation of the inching pedal 60, and one of the inflow ports is selected by the displacement of the inching rod, and the first outflow port 54c corresponding to the first inflow port 54a and the second inflow port 54b are associated. Oil is sent from the second outflow port 54d to the selector valve 61 via a pipe line.
The selector valve 61 is switched based on the operation of the clutch switching device 62, feeds hydraulic oil from the inching valve 54 to the forward clutch 57 or the reverse clutch 58, and controls the connection of both clutches 57, 58.

When the inching pedal 60 is not operated (non-inching state), the hydraulic oil conditioned by the throttle valve and accumulator 59 is sent from the oil pump 52 to the clutches 57 and 58 through the selector valve 61.
Further, when the inching pedal 60 is operated, the inching valve 54 drains a part of the hydraulic oil flowing from the oil pump 52 as surplus oil from the third outlet port 54e according to the operation amount of the inching pedal 60. By returning to the tank via the pipe line, the pressure of the hydraulic oil sent to the selector valve 61 is reduced, and the reduced hydraulic oil is sent to the clutches 57 and 58 through the selector valve 61.

For this reason, during the inching operation, the pressure of the hydraulic oil sent to the forward clutch 57 or the reverse clutch 58 becomes low, and the clutches 57 and 58 are held in a half-clutch state.
As a result, during the inching operation, the forklift travels at a low speed in a half-clutch state.

Incidentally, the inching pedal 60 and the inching valve 54 in FIG. 3 are connected by an inching cable 63, and the inching pedal 60, the inching valve 54 and the inching cable 63 constitute an inching device.
The inching valve 54 includes an inching rod, an inching spool, and a hydraulic chamber that are not shown in FIG.
The inching spool is displaced relative to the inching rod in accordance with the balance between the pressure in the hydraulic chamber and a spool coil spring (not shown) that applies a biasing force to the inching spool.

In the conventional inching device, the inching spool is displaced due to the pressure fluctuation of the hydraulic chamber in the inching valve 54. For example, when the inching pedal 60 is suddenly operated, the pressure in the hydraulic chamber can follow the operation of the inching pedal 60. The proper pressure may not be reached.
In this case, the inching spool may vibrate and collide with the inching rod, generating abnormal noise or vibration.
When the vibration increases, the vibration is transmitted to the inching pedal 60 through the inching cable 63, and unpleasant vibration may be transmitted to the sole of the driver.

As another related art, for example, there is a connector for a cable-type operating device disclosed in Patent Document 1.
This type of cable-type operating device connector is one in which one end is connected to an operating rod provided in the passenger compartment and the other end of the cable routed in the vehicle body is connected to the transmission.
The connector has a plate-like elastic body in which a through hole for inserting a connection pin provided in the transmission is formed in the thickness direction and an insertion hole from the outer periphery to the through hole is formed, and one end is a through hole A rigid rod-like member that is inserted into the insertion hole so as to face the length of the insertion hole, and has a length shorter than the depth of the insertion hole, and surrounds the elastic body so that the other end of the rod-like member faces the inner peripheral surface, and the other end of the cable is on the outer periphery And a connected ring member.

And according to this technique, it is supposed that the vibration in the connecting pin of the transmission can be absorbed by the deformation of the elastic body.
Also, when the operating rod is operated relatively quickly, the elastic body is deformed, and the other end of the rigid rod-like member is moved to the inner peripheral surface of the ring member that moves so as to exceed the vibration amplitude of the transmission due to the elastic deformation of the elastic body. Directly abut.
For this reason, the movement of the ring member is directly transmitted to the rigid rod-like member, which is linked to the movement of the cylindrical body, and is directly transmitted to the transmission via the connecting pin.
Japanese Patent Laying-Open No. 2005-264995 (pages 5-7 and 2-6)

However, in the technique disclosed in Patent Document 1, when the operating rod is operated relatively quickly, the elastic body is deformed, and the other end of the rigid rod-shaped member directly contacts the inner peripheral surface of the ring member. Transmission vibration is transmitted to the control rod through the cable.
That is, when the operating rod is suddenly operated, the vibration from the transmission is propagated to the operating rod. Also, when using this type of connector, the second lever or the end of the cable to which the connector is connected is connected. It is necessary to change the shape according to the connector.
In particular, changing the shape of the end of the cable means that a general-purpose type cable cannot be used, resulting in a problem of increasing the manufacturing cost of the apparatus.

Incidentally, in the conventional inching device, in the configuration in which the inching cable and the inching rod are directly connected, it is usually considered that an anti-vibration means such as a metal coil spring is interposed between the cable and the rod as a countermeasure against vibration. .
However, this type of vibration countermeasure requires a sufficient space for interposing an anti-vibration means, and has a problem that it cannot be applied under conditions subject to space constraints.

  The present invention has been made in view of the above problems, and an object of the present invention is to always prevent or suppress abnormal noise and vibration caused by a collision of the inching spool with the inching valve regardless of the operating state of the inching pedal. It is in the provision of the inching device of the industrial vehicle which can do.

  To achieve the above object, the present invention comprises an inching pedal for controlling an inching operation, an inching valve operated by the inching pedal, an inching cable for connecting the inching pedal and the inching valve, and the inching The valve is an inching device for an industrial vehicle having an inching rod that slides in the valve cylinder by operation of an inching pedal, and an inching spool whose position is defined by the fluid pressure in the valve cylinder. Are divided into a cable side rod body on the inching cable side and a spool side rod body on the inching spool side, and an elastic body is interposed between the cable side rod body and the spool side rod body. It is characterized by that.

According to the present invention, the elastic body absorbs vibration even when the inching rod that slides in the valve cylinder by operating the cable receives vibration from the transmission through the hydraulic circuit.
Since the elastic body of the inching rod absorbs vibration, the propagation of vibration to the inching pedal through the inching cable is prevented or suppressed.
In addition, by operating the inching pedal abruptly, even when the inching spool collides with the inching rod, the elastic body absorbs the impact of the collision.
Therefore, it is possible to always prevent or suppress abnormal noise and vibration due to the collision of the inching spool with the inching valve regardless of the operating state of the inching pedal.

  In the present invention, in the inching device for an industrial vehicle, the elastic body may be formed of a rubber-based material.

In this case, since the elastic body is formed of a rubber-based material, it is possible to expect a damping effect that the elastic body not only absorbs the impact but also quickly attenuates the vibration of the inching rod.
Further, since the elastic body is a rubber-based material, for example, the installation space can be suppressed even when compared with a coil spring, which is effective when the installation space is restricted.

  ADVANTAGE OF THE INVENTION According to this invention, the inching apparatus of the industrial vehicle which can always prevent or suppress the abnormal sound and vibration by the collision with the inching valve of an inching spool irrespective of the operating state of an inching pedal can be provided.

Hereinafter, an inching device for an industrial vehicle according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
This embodiment is an inching device 10 applied to a forklift as an industrial vehicle.
FIG. 1 is a schematic view of an inching device according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of an inching valve in the inching device.

As shown in FIG. 1, the inching device 10 mainly includes an inching pedal 11 provided in a driver seat of a forklift, an inching cable 18 that connects the inching pedal 11 and the inching valve 30, and an inching valve 30. Yes.
The inching pedal 11 has a pedal lever 13 that rotates with respect to a fulcrum shaft 12 installed in the driver's seat, and a pedal portion 14 that is fixed to the free end of the pedal lever 13.
A torsion coil spring (not shown) for returning the pedal is wound around the fulcrum shaft 12, and when the stepping on the pedal portion 14 is released, the inching pedal 11 is returned to the original position by the urging force of the torsion coil spring.

The stepping amount d of the inching pedal 11 is defined by the rotation range of the pedal lever 13 with respect to the fulcrum shaft 12.
An inching pedal 11 indicated by a solid line indicates a state in which the stepping on the pedal portion 14 is released, and an inching pedal 11 indicated by a two-dot chain line indicates a state where the pedal portion 14 is depressed.
In the vicinity of the fulcrum shaft 12 of the pedal lever 13, a protrusion 15 protruding forward is formed, and a through hole 16 for connecting to the inching cable 18 is formed in the protrusion 15.

The inching cable 18 includes an inner cable 19 connected to the inching pedal 11 and the inching valve 30, and an outer cable 20 that covers the inner cable 19.
The inner cable 19 is slidable inside the outer cable 20, and clevises 21 that are connecting tools are provided at both ends of the inner cable 19.
The pin 22 included in one clevis 21 is inserted into the through hole 16 in the protrusion 15 of the pedal lever 13 so that the pedal lever 13 and the inner cable 19 are connected.

Another clevis 21, which is the other coupling tool, is coupled to the end of the inching rod 34 in the inching valve 30.
Each end of the outer cable 20 is fixed to brackets 23 and 24 attached to the vehicle body of the forklift.
For this reason, the inner cable 19 slides with respect to the outer cable 20 when the inching pedal 11 is stepped on and released.

The inching valve 30 includes a valve cylinder 31 that holds the inching rod 34 and an inching spool 41 that slides relative to the inching rod 34.
The valve cylinder 31 is formed with a through hole 32 for accommodating the inching rod 34, and one opening of the through hole 32 is closed by a closing member 33.
The valve cylinder 31 is formed with ports P1 to P7 that communicate with the pipelines in the hydraulic circuit of the clutch hydraulic control device (for example, see FIG. 3). The ports P1 to P7 are located in the valve cylinder 31. It is formed so as to be communicated or blocked depending on the position of the inching rod 34 that slides on the surface.
In each of the ports P1 to P7, hydraulic oil as a fluid passes or is blocked according to the displacement of the inching rod 41.

The inching rod 34 is configured to move in a direction protruding from the valve cylinder 31 when the inching pedal 11 is depressed. However, the inching rod 34 is a rod for applying a biasing force to the valve cylinder 31 in a direction to push the inching rod 34 into the valve cylinder 31. A coil spring 37 is provided.
When the inching pedal 11 is released, the rod coil spring 37 applies a biasing force to the inching rod 34 to return the inching rod 34 to the original position.

The inching rod 34 will be described in detail. The inching rod 34 is divided into a cable side rod body 35 located on the inching cable 18 side in the axial direction and a spool side rod body 36 located on the inching spool 41 side.
In this embodiment, as shown in FIG. 2, a cylindrical protrusion 36 a is formed at the center of the spool side rod body 36, and the protrusion of the spool side rod body 36 is formed at the center of the cable side rod body 35. A recess 35a into which the portion 36a can be inserted is formed.
A through hole 35 b is formed at the end of the cable side rod body 35, and the pin 22 of the clevis 21 provided in the inner cable 19 is inserted into the through hole 35 b to connect the inching rod 34 and the inching cable 18.

An elastic body 38 is interposed between the gap 35a and the protrusion 36a, that is, between the cable side rod body 35 and the spool side rod body 36.
The elastic body 38 is formed of a rubber-based material, and this rubber-based material is excellent in shock absorption and vibration damping performance.
Further, since the elastic body 38 is interposed between the cable side rod body 35 and the spool side rod body 36, the elastic body 38 has a substantially cylindrical shape.
The elastic body 38 has a sufficient surface area in contact with both 35 and 36, and the impact absorption and vibration damping performance of the elastic body 38 is improved as the surface area is increased.

Further, since the elastic body 38 is formed of a rubber-based material, a sufficient “tightening allowance” for connecting the cable side rod body 35 and the spool side rod body 36 can be secured, which is combined with the securing of the surface area. Therefore, it is easy to secure a sufficient frictional force for connecting the both 35 and 36.
The cable-side rod body 35 and the spool-side rod body 36 are in non-contact with each other by the interposition of the elastic body 38, and the inching rod 34 integrated by the connection via the elastic body 38 that increases the frictional force in the radial direction is provided. Composed.

A bottomed hole 39 in which the inching spool 41 is accommodated is formed inside the inching rod 34, and the opening of the bottomed hole 39 is closed by a closing member 40.
The inching spool 41 slides and displaces in a direction that coincides with the sliding direction of the inching rod 34.
The inching spool 41 has a shape that divides the space formed by the bottomed hole 39 in the axial direction into two.
Another space for facing the bottom side of the bottomed hole 39 is provided with another coil spring 42 for spool that biases the inching spool 41 toward the closing member 40 side.
The other space portion forms a part of the hydraulic chamber 43 in which the inching pressure as the fluid pressure is set.

The hydraulic chamber 43 is formed by the valve cylinder 31, the inching rod 34, and the inching spool 41. As shown in FIG. 2A and FIG. 2B, the hydraulic chamber 43 is displaced by the displacement of the inching spool 41. The area varies.
The inching spool 41 is displaced according to the balance between the pressure in the hydraulic chamber 43 and the biasing force of the spool coil spring 42.
That is, the inching spool 41 is displaced by the pressure fluctuation of the hydraulic chamber 43, and the inching pressure is obtained by the balance between the pressure of the hydraulic chamber 43 and the biasing force of the spool coil spring 42.

Next, the operation of the inching device 10 of this embodiment will be described.
First, in a state where the inching pedal is not depressed, the inching rod 34 in the inching valve 30 is in a state where it enters the valve cylinder 31 most as shown in FIG.
In this state, the hydraulic oil flows into the port P3 communicating with the piping of the accumulator (not shown), and the hydraulic oil is supplied to the clutch through another port P2.
At this time, the flow rate of hydraulic oil supplied to the clutch is an amount that can be maintained in a state where the clutch is completely connected.
Incidentally, a region communicating with the ports P2 and P3 functions as the hydraulic chamber 43 (see the shaded portion in FIG. 2A).

When the shift lever is switched to a position to advance the vehicle in this state, hydraulic oil is supplied to the forward clutch, the forward clutch is completely connected, and the vehicle travels forward.
On the other hand, when the shift lever is switched to a position for moving the vehicle backward, hydraulic oil is supplied to the reverse clutch, and the reverse clutch is completely connected and the vehicle travels backward.

When the inching pedal 11 is depressed halfway (about half of the “stepping allowance” d), the inching rod 34 moves to the position shown in FIG.
At this time, a region communicating with the ports P2, P4, and P5 functions as the hydraulic chamber 43 (see the shaded portion in FIG. 2B).
In this state, the flow rate of the hydraulic oil to the clutch is in a state where the clutch is held in a half-clutch state.
For this reason, the driving torque transmitted through the clutch is reduced, and the vehicle is inching.
When the inching pedal 11 is depressed to the maximum, although not shown, the inching rod 34 moves to a position where the supply of hydraulic oil to the clutch is shut off.

By the way, the pressure of the hydraulic chamber 43 in the inching valve 30 varies in accordance with the operation of the inching pedal 11, and the inching spool 41 is displaced with respect to the inching rod 34 in response to the pressure variation of the hydraulic chamber 43.
The inching rod 34 that slides in the valve cylinder 31 by the operation of the inching pedal 11 may receive vibration from the transmission through a hydraulic circuit.
When the operation of the inching pedal 11 is intense, the pressure fluctuation in the hydraulic chamber 43 does not immediately follow the operation of the inching pedal 11, the inching spool 41 is greatly displaced, and the inching spool 41 collides with the inching rod 34. Sometimes.

The vibration from the transmission and the collision of the inching spool 41 are propagated to the spool side rod body 36 of the inching rod 34.
Since the elastic body 38 is formed of a rubber material excellent in shock absorption and vibration damping performance, the vibration and impact transmitted to the spool side rod body 36 are absorbed by the elastic body 38 and the vibration is quickly attenuated. Done.
Further, the impact caused by the collision with the inching rod 34 is absorbed by the elastic body 38.
For this reason, the vibration from the transmission and the impact shock are not propagated to the inching cable 18 connected to the inching rod 34, and the driver operating the inching pedal 11 does not feel an unpleasant impact or vibration on the sole of the foot. Almost no.
Further, the presence of the elastic body prevents or reduces abnormal noise generated in the inching valve.

The inching device 10 according to the embodiment of the present invention has the following effects.
(1) Even when the inching rod 34 that slides in the valve cylinder 31 by the operation of the inching pedal 11 receives the vibration generated in the hydraulic circuit, the elastic body 38 can absorb the vibration. For this reason, vibration to the inching pedal 11 through the inching cable 18 is prevented or suppressed. Further, by operating the inching pedal 11 abruptly, even when the inching spool 41 collides with the inching rod 34, the elastic body 38 can absorb the impact of the collision. Therefore, regardless of the operating state of the inching pedal 11, it is possible to always prevent or suppress abnormal noise and vibration due to the collision of the inching spool 41 with the inching rod 34.

(2) Since the elastic body 38 is formed of a rubber-based material, the elastic body 38 is not limited to absorbing the impact, and a damping effect that attenuates the vibration of the inching rod 34 can be expected. Further, since the elastic body 38 is a rubber-based material, for example, the installation space can be reduced as compared with the case where a metal coil spring is used as the elastic body, which is effective when the installation space is restricted. is there.

(3) In addition to changing the structure of the inching rod 34, it is only necessary to prepare the elastic body 38, so there is no need to change the end of the inching cable 18 to a dedicated shape, and a general-purpose inching cable 18 is used. be able to. Furthermore, the existing inching device can be changed to the inching device 10 provided with the elastic body 38 by exchanging the inching rod 34.

The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the invention. For example, the following modifications may be made.
In the above embodiment, a cylindrical protrusion is formed on the spool-side rod body, and a recess into which the protrusion of the spool-side rod body can be inserted is formed on the cable-side rod body, and a gap between the protrusion and the recess is formed. Although the elastic body is interposed between the cable-side rod body and the spool-side rod body, the shape of the elastic body interposed between the spool-side rod body and the cable-side rod body is not particularly limited. The shape may correspond to the shape of the connection side end of the spool side rod body and the cable side rod body and can eliminate the vibration and impact in the axial direction of the inching rod.
In the above embodiment, the elastic body is formed of a rubber-based material. However, the elastic body is not limited to the rubber-based material, and any material can be used as long as the performance of shock absorption or vibration damping is the same or approximate.

It is the schematic of the inching apparatus of the forklift which concerns on embodiment of this invention. It is a longitudinal cross-sectional view of the inching valve which concerns on embodiment of this invention, (a) shows a non-inching state, (b) shows an inching state. It is a hydraulic circuit diagram which shows the outline | summary of the conventional clutch hydraulic control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inching device 11, 60 Inching pedal 13 Pedal lever 14 Pedal part 18, 63 Inching cable 21 Clevis 30 Inching valve 31 Valve cylinder 34 Inching rod 35 Cable side rod body 36 Spool side rod body 37 Rod coil spring 38 Elastic body 39 Existence Bottom hole 41 Inching spool 42 Spool coil spring 43 Hydraulic chamber 50 Clutch hydraulic control devices 54a to 54e, P1 to P7 Port d

Claims (2)

An inching pedal for controlling the inching operation, an inching valve operated by the inching pedal, and an inching cable for connecting the inching pedal and the inching valve. The inching valve is operated in the valve cylinder by operating the inching pedal. In an inching device for an industrial vehicle having an inching rod that slides and an inching spool whose position is defined by the fluid pressure in the valve cylinder,
The inching rod is divided into a cable side rod body on the inching cable side in the axial direction and a spool side rod body on the inching spool side, and between the cable side rod body and the spool side rod body. An inching device for an industrial vehicle, characterized in that an elastic body is interposed. 2. The inching device for an industrial vehicle according to claim 1, wherein the elastic body is made of a rubber material.

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