JPH0663409U - Reach type forklift suspension device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a suspension device for a rear wheel of a reach type forklift truck that suppresses slip of the drive wheel by forcibly changing the wheel pressure of the drive wheel. [Structure] A drive unit 11, a parallel link 30 for suspending the drive unit 11 on a vehicle body frame 13,
The suspension device 10 includes a caster unit 20, a caster link 34, and a connecting member 15 that connects one end of the parallel link 30 and an end portion 341 of the caster link 34. The caster unit 20 has an auxiliary wheel 21, a caster arm 22 on which the auxiliary wheel 21 is mounted, and an actuator 25. The actuator 25 drives the caster arm 22 to move the auxiliary wheel 21 up and down with respect to the road surface.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a suspension device for the rear wheels of a reach-type forklift truck, and more particularly to a structure for changing the wheel pressure of its drive wheels.

[0002]

[Prior art]

 Fig. 5 shows a rear wheel suspension device for a reach-type forklift truck that has a single drive wheel at the rear wheel. That is, the drive unit 90 having the drive wheel 91 is attached to the vehicle body frame 95 via the suspension spring 92, the upper link 931 and the lower link 94, while the caster unit 97 having the auxiliary wheel 96 is attached via the caster link 933. It is attached to the body frame 95. The drive unit 90 and the caster unit 97 are joined by gently connecting the right arm 941 of the lower link 94 and the right end portion 934 of the caster link 933 via the connecting member 98.

The upper link 931 has one end rotatably attached to the vehicle body frame 95 via a second node 936, and the other end rotatably supports the drive unit 90 via a fifth node 939. It is attached to the frame 901. On the other hand, the lower link 94 has a center portion rotatably attached to the vehicle body frame 95 via the first node 935, and the right arm 941 and the left arm 942 are arranged to the left and right around the first node 935. And have. The left end portion of the left arm 942 is connected to the sub bracket 902 fixed to the drive unit 90 via the fourth node 938.

The drive unit 90 is supported by the vehicle body frame 95 by parallel links formed of parallelograms connecting the first, second, fifth, and fourth nodes 935, 936, 939, 938. Further, the suspension spring 92 provided between the drive unit 90 and the body frame 95 has a function of cushioning and changing the wheel pressure of the drive wheel 91.

A right end portion of the right arm 941 and a right end portion 934 of the caster link 933 are loosely connected to each other through a connecting member 98 with play, and a cushioning member is provided between the two members 941 and 933. The caster spring 99 is installed. The caster link 933 is rotatably attached to the vehicle body frame 95 via the third node 937.

When the upper link 931 and the lower link 94 rotate counterclockwise about the second node 936 and the first node 935, respectively, the caster link 933 connected by the connecting member 98 also has the connecting member 98. After absorbing the play in, it rotates counterclockwise about the third node 937. Then, the auxiliary wheels 96 are lifted from the surface of the earth, and the wheel pressure of the drive wheels 91 is increased.

[0007]

[Problems to be solved]

 However, the above-mentioned conventional suspension device is a so-called automatic wheel pressure system that does not have a means for artificially changing the wheel pressure of the drive wheels, and has an effective deterrent function against slip phenomena such as when the road surface freezes. I don't have it. In other words, the wheel pressure of the drive wheels is automatically determined by the load conditions and road surface conditions, and there is no function to artificially adjust the wheel pressure in order to escape from slip.

On the other hand, it is known that an operation for increasing the wheel pressure of the drive wheels is effective for suppressing the slip of the drive wheels. In view of the above-mentioned conventional problems, the present invention intends to provide a suspension device for a rear wheel of a reach type forklift truck that can suppress the slip of the driving wheel by forcibly changing the wheel pressure of the driving wheel. It is a thing.

[0009]

[Means for solving the problem]

 According to the present invention, a drive unit having drive wheels, a parallel link suspending the drive unit on a vehicle body frame so that the drive unit can be vertically swung, a caster unit having auxiliary wheels, and the caster unit can be vertically swung. A suspension device for a rear wheel of a reach-type forklift truck having caster links suspended on the vehicle body frame and a connecting member for connecting one end of the parallel link and the end of the caster link as described above. The caster unit has an auxiliary wheel, a caster arm on which the auxiliary wheel is mounted, and an actuator that drives the caster arm. The actuator drives the caster arm to face the auxiliary wheel to the road surface. Suspension device for rear wheels of reach type forklift trucks It is in.

What is most noticeable in the present invention is that the caster unit has an actuator for driving the caster arm, and the caster arm is driven by the actuator to move the auxiliary wheels up and down. is there. That is, an auxiliary wheel is attached to the caster arm, and the actuator moves the auxiliary wheel up and down with respect to the ground by, for example, expanding and contracting the caster arm itself or changing the mounting angle of the caster arm with respect to the vehicle body. Let Such actuators include various cylinder devices and electric motors. The actuator may be operated by the driver, or a sensor for detecting slip may be separately provided for automatic control.

[0011]

[Action and effect]

 In the suspension device according to the present invention, the auxiliary wheels can be moved up and down by operating the actuator. When the auxiliary wheels are raised, the auxiliary wheels are separated from the road surface, and the rear wheel load concentrates on the drive wheels, increasing the wheel pressure of the drive wheels. On the contrary, if the actuator is operated in the direction to further lower the auxiliary wheels while the auxiliary wheels are in contact with the road surface, the wheel pressure of the drive wheels will decrease.

On the other hand, when the drive wheels slip, if the wheel pressure can be increased, the slip of the drive wheels can be suppressed. Therefore, when the drive wheel slips, the suspension device of the present invention can suppress the drive wheel slip by operating the actuator to raise the auxiliary wheel from the road surface. As described above, according to the present invention, it is possible to provide a suspension device for a rear wheel of a reach type forklift truck that can suppress the slip of the drive wheel by forcibly changing the wheel pressure of the drive wheel. .

[0013]

【Example】

 A rear wheel suspension device for a reach type forklift truck according to an embodiment of the present invention will be described with reference to FIGS. In this example, as shown in FIG. 1, a drive unit 11 having drive wheels 12, a horizontal link 30 that suspends the drive unit 11 on a vehicle body frame 13 so that the drive unit 11 can be vertically swung, and a caster having auxiliary wheels 21. The unit 20, the caster link 34 that suspends the caster unit 20 on the vehicle body frame 13 so that the caster unit 20 can swing up and down, and the connecting member 15 that connects one end of the parallel link 30 and the end portion 341 of the caster link 34. It is a rear wheel suspension device 10 having a reach type forklift truck having.

The caster unit 20 has an auxiliary wheel 21, a caster arm 22 for mounting the auxiliary wheel 21, and an actuator 25 for driving the caster arm 22, and the actuator 25 is The caster arm 22 is driven to move the auxiliary wheel 21 up and down.

Each of these will be described in detail below. As shown in FIG. 1, the drive unit 11 of the suspension device 10 has drive wheels 12 mounted on its support frame 14, and the drive wheels 12 are driven by a drive motor (not shown). The drive unit 11 is attached to the vehicle body frame 13 via a cushioning suspension spring 18 and a parallel link 30.

The parallel link 30 has an upper link 31 connected to an upper portion of the support frame 14, and a lower link 32 connected to a lower portion of a sub-bracket 141 fixed to the support frame 14. The right end of the upper link 31 is rotatably supported by the vehicle body frame 13 via the second node 36, and the left end of the upper link 31 is supported by the support frame 14 of the drive unit 11 via the fifth node 39. It is rotatably supported on the upper part.

On the other hand, the lower link 32 has its central portion pivotally supported at the first node 35, and is rotatably connected to the vehicle body frame 13. Then, the left arm 321 and the right arm 322 swing in opposite directions in a seesaw shape. The left end of the left arm 321 is pivotally supported by the fourth node 38 and is rotatably connected to the lower portion of the sub bracket 141.

That is, the drive unit 11 is supported by a parallel link 30 formed of a parallelogram connecting the first, second, fifth and fourth nodes 35, 36, 39, 38 and suspended from the vehicle body frame 13. There is. The drive wheel 12 is in contact with the road surface due to the wheel pressure that varies depending on the set length S (FIG. 1) of the suspension spring 18. The right end 3221 of the right arm 322 of the lower link 32 is loosely connected to the right end 341 of the caster link 34 via the connecting member 15.

On the other hand, the caster link 34 has its left end pivotally supported by the vehicle body frame 13 via a third node 37, and the caster unit 20 is suspended on the right side thereof. Then, as described above, the right end portion 341 of the caster link 34 and the right end portion 3221 of the lower link 32 are gently connected to each other through the connecting member 15 so as to have a play.

That is, the right end portion 341 of the caster link 34 and the right end portion 3221 of the lower link 32 slide through the connecting member 15 and between the stop members provided above and below the connecting member 15. A buffer caster spring 19 is provided between the caster link 34 and the right arm 322 of the lower link 32.

The caster unit 20 has an auxiliary wheel 21, a caster arm 22, and an actuator 25. As shown in FIG. 2, the caster arm 22 has a main arm 23 connected to the caster link 34 and a sub arm 24 to which the auxiliary wheel 21 is attached. The upper part of the main arm 23 is connected to the caster link 34 via a bearing 231 and rotates about its axis 232.

On the other hand, the sub-arm 24 has an upper part attached to a rotary shaft 26 provided at a lower part of the main arm 23, and an auxiliary wheel 21 attached to a lower part thereof. The rotary shaft 26 is connected to the stepping motor 251 of the actuator 25 and driven by the stepping motor 251 to rotate about its rotary shaft 261 as shown in FIGS. As a result, the auxiliary wheel 21 moves up and down with respect to the road surface 4.

The actuator 25 rotates the rotating shaft 26 using the stepping motor 251 as a drive source. The stepping motor 251 is connected to a ring-shaped electrode 252 provided on the upper surface of the main arm 23 as shown in FIG. 2, and the electrode 252 is stepped through a brush 253 which slides on the electrode 252. It is connected to a drive device (not shown) of the motor 251.

Next, the function and effect of the suspension device 10 of this example will be described. In the suspension device 10 of the present example, the rotary shaft 26 is rotated by being driven by the actuator 25, and as shown in FIG. 4, the angle θ formed by the sub arm 24 and the main arm 23 changes. Then, the auxiliary wheel 21 rises by Δh with respect to the road surface 4, as shown in FIG. As a result, the wheel pressure of the drive wheels 12 on the road surface 4 increases.

Therefore, when the drive wheel 12 slips, if the actuator 25 is driven to raise the auxiliary wheel 21, the wheel pressure of the drive wheel 12 increases and the slip of the drive wheel 12 can be suppressed. Further, since the stepping motor 251 can raise the auxiliary wheels 21 with good responsiveness and at extremely high speed, it is possible to quickly suppress the slip.

The operation of the actuator 25 can be performed by the operation of the driver, and a slip sensor for detecting the slip of the driving wheels can be separately provided and automatically operated. It is also possible to provide an automatic / manual changeover switch so that both the above-mentioned automatic operation and manual operation can be switched. As described above, according to the suspension device of the present embodiment, the suspension device for the rear wheels of the reach type forklift truck that can suppress the slip of the driving wheels by forcibly changing the wheel pressure of the driving wheels is provided. can do.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a suspension device according to an embodiment.

FIG. 2 is a partially enlarged explanatory view of a caster unit portion of the suspension device according to the embodiment.

FIG. 3 is a side view of the caster unit shown in FIG.

FIG. 4 is a side view when the sub arm is rotated in FIG.

FIG. 5 is an explanatory diagram of a conventional suspension device.

[Explanation of symbols]

 10. ． ． Suspension device, 11. ． ． Drive unit, 12. ． ． Drive wheel, 13. ． ． Body frame, 15. ． ． Connection member, 20. ． ． Caster unit, 21. ． ． Auxiliary wheel, 25. ． ． Actuator, 30. ． ． Parallel links, 34. ． ． Castor Link,

Claims (1)

[Scope of utility model registration request] 1. A drive unit having drive wheels, a parallel link suspending the drive unit on a vehicle body frame so as to be able to swing up and down, a caster unit having auxiliary wheels, and the caster unit being swingable up and down. A suspension device for a rear wheel of a reach type forklift truck having caster links suspended on a vehicle body frame and a connecting member for connecting one end of the parallel link and an end of the caster link as described above, wherein the caster unit comprises: It has an auxiliary wheel, a caster arm on which the auxiliary wheel is mounted, and an actuator for driving the caster arm. The actuator drives the caster arm to move the auxiliary wheel up and down with respect to the road surface. A rear wheel suspension system for a reach truck forklift truck.