JP5904612B1 - forklift - Google Patents

Abstract

A forklift capable of braking a road wheel while ensuring the swingability of a wheel unit is provided. A wheel unit 4 is housed in a straddle leg 2 so as to be swingable in a front-rear direction X. The wheel unit 4 includes a pair of support plates 40 arranged in the left-right direction Y, a pair of road wheels 41 arranged in the front-rear direction X between the pair of support plates 40, and a pair of road wheels 41. And two wheel shafts 42 inserted in the left-right direction Y and rotatably supported by the pair of support plates 40. Each wheel shaft 42 includes an extension 47 extending outside the straddle leg 2. A brake unit 5 is provided that is connected to the extension 47 of each wheel shaft 42 and brakes each road wheel 41. The brake unit 5 is configured to swing in the front-rear direction X integrally with the wheel unit 4. [Selection] Figure 3

Description

  The present invention relates to a forklift in which a wheel unit having a pair of front and rear road wheels is provided on a straddle leg.

  FIG. 5 discloses a conventional forklift. This forklift is a three-way stacking truck. The forklift includes a pair of straddle legs 80 extending forward from the left and right sides of the lower portion of the vehicle body 8 and a cargo handling device 81 provided between the pair of straddle legs 80 in front of the vehicle body 8. The cargo handling device 81 moves the fork 82 up and down, horizontally moves the fork 82 in the left-right direction, and turns the fork 82 180 degrees around the vertical axis to the left, front, and right. The forklift can deliver the load to the front, left, and right three directions by the cargo handling device 81.

  In order to allow a forklift to deliver a load even at a low position, a load wheel provided on each straddle leg 80 generally has a small diameter. When delivering a load to the left or right, the load is concentrated on the small-diameter road wheel, but the load resistance is too small with only one small-diameter road wheel.

  Therefore, as shown in FIG. 6, a wheel unit 9 including two road wheels 90 is employed. The pair of road wheels 90 are arranged in the front-rear direction X, and each is rotatably supported by a wheel shaft 91 extending in the left-right direction Y via a bearing 92 inside thereof. Both ends of the wheel shaft 91 are supported by a pair of support plates 93.

  As shown in FIG. 7, an accommodation frame for accommodating the wheel unit 9 is provided at the tip of the straddle leg 80. The housing frame includes a frame body 83 (FIG. 7B) of the straddle leg 80, a side frame 84 extending from the left and right sides in the front-rear direction X, and a front frame 85 provided at the front end of the side frame 84. As shown in FIG. 7A, the side frame 84 is formed with a substantially rectangular notch 86 that opens downward, and a cover plate 87 is attached to the outer surface of the side frame 84 to cover the notch 86. And the protrusion part 86a is formed so that it may protrude below from the center of the top | upper surface of the notch 86. FIG.

  The forklift is lifted with a crane or the like to lift the straddle leg 80 from the floor, and the wheel unit 9 is moved below the housing frame. Then, the wheel unit 9 is housed in the housing frame by lowering the forklift. When the wheel unit 9 is housed in the housing frame, the pair of support plates 93 are disposed in the notches 86, and the protruding portions 86 a come into contact with the upper surface of the support plate 93. As a result, the wheel unit 9 can swing in the front-rear direction X within the housing frame with the contact point with the protrusion 86a as a fulcrum.

  According to this configuration, even if there is unevenness on the road surface or uneven wear in which one of the pair of road wheels 90 is worn unevenly, the wheel unit 9 swings correspondingly, and the pair of road wheels 90 Each wheel load is even. Such a mechanism is called an equalizer mechanism (see Patent Documents 1, 2, 3, etc.).

JP 2006-69750 A JP 2006-56646 A JP 2000-7294 A

  By the way, in the vehicle body 8 of this forklift, as shown in FIG. 5B, the drive tire 89 is provided offset to the left from the central axis C of the vehicle body 8 because of the space where the driver's seat 88 is provided. When the forklift brakes and brakes the drive tire 89 due to the offset of the drive tire 89, a yaw moment is generated to turn the vehicle body 8 (an arrow extending from the central axis C in FIG. 5B). The vehicle body 8 is shaken.

  In order to ensure the safety of the forklift, it is necessary to generate a force that cancels the yaw moment to prevent the vehicle body 8 from shaking. As a method of canceling the yaw moment, for example, there is a method of braking each of the road wheels 90 by providing a brake on the right wheel unit 9 in the direction opposite to the offset direction of the drive tire 89.

  However, it has been impossible to brake each road wheel 90 without oscillating the wheel unit 9, that is, without sacrificing the equalizer mechanism.

  Therefore, an object of the present invention is to provide a forklift capable of braking a road wheel while ensuring the swingability of the wheel unit.

In order to solve the above-described problems, a forklift according to the present invention includes a vehicle body, a pair of straddle legs extending forward from the left and right sides of the lower portion of the vehicle body, and at least one of the above-described swingable front and rear directions. A wheel unit provided in the straddle leg,
The wheel unit is inserted into the pair of load wheels and a pair of support plates disposed in the left-right direction, a pair of load wheels disposed in the front-rear direction between the pair of support plates. Two wheel shafts extending in the direction and rotatably supported by the pair of support plates, each wheel shaft including an extension extending outside the straddle leg,
The brake unit is connected to the extension of each wheel shaft and brakes each road wheel, and the brake unit is configured to swing in the front-rear direction integrally with the wheel unit. It is characterized by that.

  Preferably, the brake unit is connected to the extension of the wheel shaft at the front, and is connected to the first unit for braking the road wheel at the front, and to the extension of the wheel shaft at the rear, And a second unit for braking the road wheel at the rear.

Preferably, wherein each of the first unit and the second unit comprises an electromagnetic brake to generate a braking torque for braking the road wheels, a reduction gear for amplifying a pre Symbol braking torque, and
The electromagnetic brake includes a rotating shaft for transmitting the brake torque to the speed reducer, and the speed reducer is connected to the extension portion of the rotating shaft and the wheel shaft and is generated by the electromagnetic brake. Torque is amplified and transmitted to the wheel shaft and the road wheel .

  Preferably, the electromagnetic brake is a non-excitation type.

  Preferably, a drive tire is provided in the vehicle body offset leftward or rightward from a central axis of the vehicle body, and the brake unit is provided in the straddle leg in the direction opposite to the offset direction of the drive tire. It is provided in the wheel unit.

  Preferably, each extension portion extends toward a central axis of the vehicle body, and the brake unit is located in a space between the pair of straddle legs.

  Preferably, the wheel unit includes a connecting member attached to the pair of support plates so as to connect the pair of support plates to each other, and the support that is distal to the brake unit of the pair of support plates. The plate can be removed from the connecting member, and when the support plate is removed, the pair of load wheels can be taken out.

  Preferably, the forklift is disposed between the pair of straddle legs in front of the vehicle body, and includes a cargo handling device that moves the fork up and down, moves left and right, and swivels around a vertical axis. It is.

  ADVANTAGE OF THE INVENTION According to this invention, the forklift which can brake a road wheel can be provided, ensuring the rocking | fluctuation property of a wheel unit.

1 shows a schematic configuration of a forklift according to an embodiment of the present invention, FIG. 1A is a side view, and FIG. 1B is a plan view. It is a top view which shows the internal structure of a wheel unit and a brake unit. It is a top view of the front-end | tip part of the straddle leg in which the wheel unit was accommodated. It is an AA arrow directional side view of FIG. FIG. 5A is a side view and FIG. 5B is a plan view showing a conventional forklift. It is a top view of the wheel unit with which the conventional forklift is equipped. FIG. 7A is a side view and FIG. 7B is a plan view showing a straddle leg in which a wheel unit is accommodated.

  Hereinafter, a forklift according to the present invention will be described with reference to the drawings. The forklift according to this embodiment is a three-way stacking truck.

  Referring to FIG. 1, the forklift includes a vehicle body 1 having a driver's seat 10 and a drive tire 11 as a rear wheel. The forklift is operated by an operator who gets on the driver's seat 10 in a standing posture. As shown in FIG. 1B, the driver's seat 10 is provided offset to the right from the central axis C of the vehicle body 1, and the drive tire 11 is provided offset to the left from the central axis C. In the vehicle body 1, a travel control device 12 that controls steering, driving, and braking of the drive tire 11 is provided.

  Further, the forklift includes a pair of straddle legs 2 that extend forward from the left and right sides of the lower portion of the vehicle body 1. Each straddle leg 2 is provided with a wheel unit 4 to be described later.

  Further, the forklift includes a cargo handling device 3 between the pair of straddle legs 2 in front of the vehicle body 1. The cargo handling device 3 includes a mast device that raises and lowers a pair of left and right forks 30, a shift device that horizontally moves the forks 30 in the left and right directions, and the fork 30 around the vertical axis 180 to the left, front, and right. And a rotation device for rotating the device. Therefore, this forklift can deliver a load in three directions: front, left, and right. In addition, since the structure of this cargo handling apparatus 3 is the same as the conventional one, its detailed description is omitted.

  The forklift includes a wheel unit 4 provided in the front end portion of each straddle leg 2 and a brake unit 5 (FIG. 1B) provided in each wheel unit 4.

  With reference to FIG. 2, the structure of the wheel unit 4 and the brake unit 5 is demonstrated. FIG. 2 shows the wheel unit 4 and the brake unit 5 on the right side. Since the wheel unit 4 and the brake unit 5 on the left side are symmetrical with respect to the right side and the central axis C, the description thereof is omitted.

  As shown in FIG. 2, the wheel unit 4 includes a pair of support plates 40 disposed facing the left-right direction Y, and a pair of road wheels 41 serving as front wheels disposed in the front-rear direction X between the pair of support plates 40. And two wheel shafts 42 inserted in the pair of road wheels 41 and extending in the left-right direction Y.

  The pair of support plates 40 are connected to each other by a connecting member 43 extending in the left-right direction Y at the front end, the center, and the rear end. The connecting member 43 is provided so as not to interfere with the rotation of the road wheel 41. The inner surfaces of the support plates 40 are in contact with the end surfaces of the connecting members 43, and these are fixed to each other by bolts 44. Each wheel shaft 42 is rotatably supported by a pair of support plates 40 via bearings 45. The load wheel 41 rotates around the axis of the wheel shaft 42 integrally with the wheel shaft 42.

  The wheel shaft 42 includes a base portion 46 that supports the road wheel 41, and an extension portion 47 that extends from one end of the base portion 46 and protrudes from the inner support plate 40 (near the central axis C) of the pair of support plates 40. And. As shown in FIG. 3, the extension 47 extends outside the straddle leg 2 and toward the central axis C of the vehicle body 1 when the wheel unit 4 is accommodated in the straddle leg 2.

  The brake unit 5 is connected to the extension 47 of each wheel shaft 42 and brakes each road wheel 41. In this embodiment, the brake unit 5 includes a base plate 50, a first unit 51, and a second unit 52.

  Each extension 47 is inserted through the base plate 50 and is rotatably supported by the base plate 50 via a bearing 53. The first and second units 51 and 52 are supported by the base plate 50. The first unit 51 is connected to an extension 47 of the wheel shaft 42 located in front, and brakes the road wheel 41 located in front. The second unit 52 is connected to the extension 47 of the wheel shaft 42 at the rear, and brakes the road wheel 41 at the rear.

  The first and second units 51 and 52 are each controlled by the travel control device 12 (FIG. 1). Each of the first and second units 51 and 52 includes an electromagnetic brake 6 that generates a brake torque for braking the road wheel 41 and a speed reducer 7 that amplifies the brake torque.

  The electromagnetic brake 6 is a non-excitation type, and a known one is adopted. The electromagnetic brake 6 includes a cover 60, a rotating shaft 61 supported rotatably with respect to the cover 60 via a bearing, a field core 62 fixed to the cover 60, a coil 63 built in the field core 62, and the like. Become. The brake plate 64 is attached to the rotating shaft 61 and rotates integrally therewith. The armature 65 is disposed so as to be movable in the axial direction of the rotary shaft 61 between the field core 62 and the brake plate 64, and is urged toward the brake plate 64 by a spring (not shown).

  The second unit 52 is provided with an encoder 66 for detecting the rotation of the rotating shaft 61 and thereby detecting the rotation of the road wheel 41. The encoder 66 is connected to the travel control device 12.

  The reducer 7 is a planetary gear type, and a known one is adopted. The speed reducer 7 includes a holding member 70 supported by the base plate 50 and a gear unit 71 held by the holding member 70. The gear unit 71 includes an internal gear, a sun gear, a planetary gear, and a carrier gear. The rotating shaft 61 of the electromagnetic brake 6 is connected to the sun gear, and the extension 47 of the wheel shaft 42 is connected to the carrier gear.

  With this configuration, when the forklift travels and the wheel shaft 42 rotates, the rotation speed is amplified by the speed reducer 7, and the rotation shaft 61 rotates at an amplified speed in conjunction with the rotation of the wheel shaft 42. In other words, the brake torque generated by the electromagnetic brake 6 is amplified by the speed reducer 7 and transmitted to the wheel shaft 42 and the road wheel 41.

  In each of the first and second units 51 and 52, when the coil 63 is not excited, the armature 65 is pressed against the brake plate 64 by a spring. As the armature 65 and the brake plate 64 are frictionally engaged with each other, a brake torque is generated, and the rotating shaft 61 is braked so as not to rotate. As a result, the wheel shaft 42 and the road wheel 41 are braked so as not to rotate. That is, the brake is applied to each road wheel 41.

On the other hand, when the coil 63 is excited, the armature 65 is attracted to the field core 62 against the biasing force of the spring and is separated from the brake plate 64. Accordingly, the rotating shaft 61 can rotate, and as a result, the wheel shaft 42 and the road wheel 41 are not braked. That is, the brake for each road wheel 41 is released.
As described above, the brake unit 5 brakes each road wheel 41.

Next, a configuration in which the wheel unit 4 is accommodated in the straddle leg 2 will be described with reference to FIGS. 3 and 4.
A housing frame having a substantially rectangular shape in a plan view for housing the wheel unit 4 is formed at the tip of the straddle leg 2. The housing frame is connected to the frame body 20 of the straddle leg 2, the side frame 21 extending forward from the left and right sides of the frame body 20 and facing each other in the left-right direction Y, and the front ends of the side frames 21. And a front frame 22 extending in the left-right direction.

  As shown in FIG. 4, each side frame 21 is formed with a substantially rectangular cutout 23 that opens downward. A cover plate 24 is attached to the outer surface of each side frame 21 and covers the notch 23. A projecting portion 25 projecting downward is formed on the top surface of the notch 23. Of the two cover plates 24, the inner cover plate 24 is formed with two opposite substantially U-shaped notches 26 opened downward.

In order to house the wheel unit 4 in the housing frame, first, the forklift is lifted by a crane or the like to lift the straddle leg 2 from the floor surface. The integrated wheel unit 4 and brake unit 5 of FIG. 2 are moved below the straddle leg 2. Then, the forklift is lowered and the wheel unit 4 is stored in the support frame. During this storage, the extension 47 of the wheel shaft 42 protruding from the support plate 40 is passed through the notch 26 of the inner cover plate 24 from below.
Thereby, the wheel unit 4 is accommodated in the straddle leg 2, while the brake unit 5 is located outside the straddle leg 2 and in a space between the pair of straddle legs 2 (see FIGS. 1B and 3).

When the wheel unit 4 is housed in the housing frame, each support plate 40 is positioned in the notch 23 of the side frame 21, and the protruding portion 25 contacts the upper surface of the support plate 40. As a result, the wheel unit 4 and the brake unit 5 can swing integrally in the front-rear direction X with the contact point as a fulcrum.
In this embodiment, the notch 26 of the cover plate 24 through which the extension 47 is inserted has a width larger than the diameter of the extension 47 so that the wheel unit 4 and the brake unit 5 can swing integrally. Must be designed to have (see FIG. 4).

  With this configuration, the road wheel 41 swings in response to road surface irregularities and uneven wear of the pair of road wheels 41, and the load applied to each of the road wheels 41 becomes equal. That is, an equalizer mechanism is realized. The brake unit 5 is configured so as to be able to swing integrally with the wheel unit 4, so that each road wheel 41 is braked while ensuring the swingability (that is, equalizing mechanism) of the wheel unit 4. Can do.

  As shown in FIG. 1B, the drive tire 11 is offset to the left from the central axis C of the vehicle body 1. Therefore, when the travel control device 12 brakes the drive tire 11 with a brake unit for the drive tire 11 (not shown), a yaw moment that tries to turn the vehicle body 1 is generated. Therefore, when braking the drive tire 11, the traveling control device 12 operates the brake unit 5 in the direction opposite to the offset direction of the drive tire 11, that is, the right side in the present embodiment, to the right side. Each road wheel 41 of the wheel unit 4 is braked. As a result, the yaw moment is canceled and the vehicle body 1 is prevented from shaking.

  From the viewpoint of shortening the braking distance, both the left and right brake units 5 may be operated when the drive tire 11 is braked. However, if both the left and right brake units 5 have the same performance and generate the same brake torque, the yaw moment cannot be canceled even if both brake units 5 are operated in the same manner. Therefore, the traveling control device 12 sets each brake unit 5 so that the work amount by the brake unit 5 in the direction opposite to the offset direction (right side) is larger than the work amount by the brake unit 5 in the offset direction (left side). By operating, the braking distance is shortened while canceling the yaw moment.

When the drive tire 11 is braked, the travel control device 12 is based on both the detection signal from the encoder 66 of the second unit 52 and the detection signal from an encoder (not shown) that detects the rotation of the drive tire 11. May be controlled. For example, the traveling control device 12 weakens or cancels the braking of the road wheel 41 when the rotation of the drive tire 11 is detected during braking and the rotation of the road wheel 41 is not detected.
Although the encoder 66 is provided only in the second unit 52, it may be provided in the first unit 51, or may be provided in both the first and second units 51 and 52.

As described above, each wheel shaft 42 of the wheel unit 4 includes the extension 47 extending outside the straddle leg 2, and the brake unit 5 is connected to each extension 47 so as to swing integrally with the wheel unit 4. It is configured. Thereby, each road wheel 41 can be braked while securing an equalizing mechanism.
The brake unit 5 is provided at least in the wheel unit 4 in the direction opposite to the offset direction of the drive tire 11, thereby canceling the yaw moment and preventing the vehicle body 1 from shaking.

  Since the brake unit 5 is located in the space between the pair of straddle legs 2, it does not collide with a rack or the like when the forklift travels. Note that the space provided between the pair of straddle legs 2 in front of the cargo handling device 3 is a space where a balance weight is conventionally arranged, but the brake unit 5 is arranged using this empty space. .

  As described in the prior art, the wheel unit 4 generally has a small diameter. Therefore, the electromagnetic brake 6 is limited in the diameter of the brake plate 64 and can generate only a small brake torque. However, when the speed reducer 7 amplifies the brake torque, the brake torque necessary for braking the road wheel 41 is ensured.

  Since the electromagnetic brake 6 is a non-excitation type, when the power is turned off due to a failure of the forklift or the like, the road wheel 41 is braked to prevent the vehicle body 1 from shaking. This prevents the vehicle body 1 from colliding with a rack or the like when the power is suddenly turned off. Such a configuration is particularly effective when the forklift is a three-way stacking truck as in the present embodiment that travels in a narrow path between racks and is an unmanned traveling type, unlike the embodiment.

  With reference to FIG. 2, in the wheel unit 4 according to the present invention, of the pair of support plates 40, the support plate 40 distal to the brake unit 5 can be removed from the connecting member 43 by removing the bolt 44. . And when this connection member 43 is removed, it is comprised so that the load wheel 41 can be taken out from the place which removed the support plate 40. FIG. Therefore, the operator can easily replace the worn road wheel 41 without touching the brake unit 5. Thus, in the forklift according to the present invention, the maintainability of the road wheel 41 is very excellent.

As mentioned above, although preferred embodiment which concerns on this invention was described, this invention is not limited to the said embodiment.
The forklift is a manned forklift in the embodiment, but may be an unmanned forklift or a manned / unmanned forklift. Further, the forklift according to the present invention is not limited to the three-way stacking truck, and may be a reach forklift having a straddle leg, for example.

  The electromagnetic brake 6 is a non-excitation type in the embodiment, but may be an excitation type. Further, for example, wet multi-plate brakes may be employed for the first and second units 51 and 52. In this case, a sufficiently large brake torque is ensured without the reduction gear 7.

DESCRIPTION OF SYMBOLS 1 Car body 11 Drive tire 2 Straddle leg 3 Cargo handling device 4 Wheel unit 40 Support plate 41 Road wheel 42 Wheel shaft 43 Connecting member 47 Extension part 5 Brake unit 51 1st unit 52 2nd unit 6 Electromagnetic brake 7 Reduction gear

Claims (8)

A vehicle body, a pair of straddle legs extending forward from the left and right sides of the lower portion of the vehicle body, and a wheel unit provided in at least one of the straddle legs so as to be swingable in the front-rear direction.
The wheel unit is inserted into the pair of load wheels and a pair of support plates disposed in the left-right direction, a pair of load wheels disposed in the front-rear direction between the pair of support plates. Two wheel shafts extending in the direction and rotatably supported by the pair of support plates, each wheel shaft including an extension extending outside the straddle leg,
The brake unit is connected to the extension of each wheel shaft and brakes each road wheel, and the brake unit is configured to swing in the front-rear direction integrally with the wheel unit. A forklift characterized by that.   The brake unit is connected to the extension portion of the wheel shaft at the front, and is connected to the extension portion of the wheel shaft at the rear and a first unit that brakes the road wheel at the front, and is at the rear The forklift according to claim 1, further comprising a second unit that brakes the road wheel. Wherein each of the first unit and the second unit comprises an electromagnetic brake to generate a braking torque for braking the road wheels, a reduction gear for amplifying a pre Symbol braking torque, and
The electromagnetic brake includes a rotating shaft for transmitting the brake torque to the speed reducer, and the speed reducer is connected to the extension portion of the rotating shaft and the wheel shaft and is generated by the electromagnetic brake. The forklift according to claim 2, wherein torque is amplified and transmitted to the wheel shaft and the road wheel .   The forklift according to claim 3, wherein the electromagnetic brake is a non-excitation type.   A drive tire is provided on the vehicle body offset leftward or rightward from the central axis of the vehicle body, and the brake unit is connected to the wheel unit in the straddle leg in a direction opposite to the offset direction of the drive tire. The forklift according to any one of claims 1 to 4, wherein the forklift is provided.   The extension portion extends toward the center axis of the vehicle body, and the brake unit is located in a space between the pair of straddle legs. The forklift according to the item.   The wheel unit includes a connecting member attached to the pair of support plates so as to connect the pair of support plates, and the support plate located distal to the brake unit of the pair of support plates The forklift according to any one of claims 1 to 6, wherein the forklift is detachable from the connecting member, and the pair of load wheels can be taken out when the support plate is removed.   The forklift is a three-way stacking truck that is disposed between the pair of straddle legs in front of the vehicle body, and includes a cargo handling device that moves the fork up and down, moves in the left-right direction, and turns around the vertical axis. The forklift according to any one of claims 1 to 7, wherein the forklift is provided.

Images