JPS6322325B2 - - Google Patents

Description

[Detailed Description of the Invention] [Background of the Invention] The present invention smoothly transmits the rotational operation force applied to the input shaft to the output shaft to rotate the output shaft, and also allows the output shaft to be rotated due to disturbance. This invention relates to a shock absorber that prevents or buffers the load from being transmitted to the input shaft side when the load is transmitted.

An example of a rotary operating device that requires this type of shock absorbing device is a steering device for an industrial vehicle. In other words, when an industrial vehicle such as a forklift has a large dead weight or a large loaded weight, if the steering wheel rides on a protrusion or is subjected to a diagonal load while the steering wheel is running, the protrusion may An excessive load caused by a disturbance such as an object or a load causes a so-called kickback phenomenon in which a steering wheel inserted by the driver of an industrial vehicle is suddenly applied, which may cause pain to the driver's arm. In the steering system of a passenger car, a worm is formed on the input shaft that inputs the rotational force of the steering wheel operated by the driver, and a worm wheel is formed on the output shaft that is connected to the steering wheel via a link. By meshing the two, the rotational operating force of the steering wheel is smoothly transmitted to the output shaft, and the load generated by disturbance to the steering wheel is buffered so that it is not transmitted to the input shaft and the steering wheel. However, some industrial vehicles have structures that make it difficult to use such a steering device, and in particular, industrial vehicles of the type that steer the drive wheels, such as reach-type forklifts, do not require the above-mentioned steering device. It is difficult to use, and the reduction ratio between the steering wheel shaft (input shaft) and the output shaft on the steering wheel side is large, and the load transmitted to the steering wheel when jerkback occurs is correspondingly large.

[Purpose of the invention]

The present invention provides input to a rotary operation shaft on which a human-powered rotational operation force is applied, such as a rotary operation shaft connected to the steering handle of a steering device as described above or an intermediate shaft between the steering handle and the steering shaft. It is divided into a shaft and an output shaft, so that the rotational operating force applied to the input shaft is smoothly transmitted to the output shaft, and when a load due to disturbance occurs on the output shaft, the load is transmitted to the input shaft. It is an object of the present invention to provide a shock absorbing device that prevents or damps the transmission of power to an input shaft.

[Structure of the invention]

The present invention includes an input shaft to which a rotational operation force is applied;
It is formed between the output shaft and the output shaft to which the rotational operating force is transmitted and rotated, so that the torque of the input shaft is smoothly transmitted to the output shaft, and when a load caused by a disturbance is transmitted to the output shaft, the output shaft In this device, the ends of the input shaft and the output shaft are disposed concentrically with the center axis of the engagement surface in a housing having a cylindrical engagement surface formed on the inner wall. and are rotatably supported by the housing, respectively, and end plates each having an end face extending in a plane perpendicular to the central axis of the engagement surface are formed at the ends of the input shaft and the output shaft, The end surfaces of the end plates of the input shaft are arranged to face each other at a predetermined interval, and the end surface of the end plate of the input shaft has a diameter of 1.
two short shafts are erected parallel to the central axis of the input shaft at positions symmetrical about the two diameter lines and radially apart from the central axis of the input shaft by a predetermined distance with respect to the diameter line; In a space formed on the input shaft and the output shaft, where the end faces face each other, two annular rollers, which are loosely fitted to each of the short shafts through a center hole, are rotatably and slidably inserted, and The end plate is provided with a periphery of the roller at a position symmetrical about a diameter line passing through the central axis of the output shaft and radially distanced from the central axis of the output shaft with respect to the diameter line. An engaging member that forms an abutting wall that abuts against the surface portion and that abuts the circumferential surface portion of the roller over a predetermined area exerts an elastic force on the two rollers in the diametrical direction of one of the output shafts. The two rollers abut each other on their peripheral surfaces due to the elastic force exerted by the engagement member, and have an outer diameter and an inner diameter that abut against the engagement surface of the housing. The present invention relates to a shock absorbing device for a rotary operation shaft, characterized by having the following features.

Further, in the present invention, preferably, the cylindrical engagement surface is formed on the inner surface of a sleeve that is formed separately from the housing and fixed to the housing, and the engagement member is formed of a spring steel plate. Alternatively, the output shaft is fixed to a sliding rod whose central axis is disposed in the diametrical direction of the one of the output shafts and is slidably supported on the end plate of the output shaft, and the output shaft is elastically moved in the diametrical direction by the sliding rod. A spring may be interposed therebetween, and the engaging member may be a leaf spring having a curved portion that abuts the circumferential surfaces of the two rollers, and the engaging member may be fixed to the sliding rod at a central portion thereof, An engaging portion that can abut against the circumferential surfaces of the two rollers can be formed at the tip of the sliding rod.

[Explanation of Examples]

FIG. 1 is a front view of a reach-type forklift steering device suitable for implementing the shock absorber for a rotary operation shaft of the present invention, and the reference numeral 20 in the figure indicates an embodiment of the shock absorber according to the present invention. . In the figure, a forklift machine frame 1 rotatably supports a driving device consisting of a prime mover housing 2 containing a motor, a steered gear 3, and a wheel support frame 4 as one unit. The rotatably supported wheels 5 are driven by a motor via a drive means (not shown) such as a chain, and the entire machine is rotated integrally with respect to the machine frame 1 for steering.

The steering mechanism supports a steering shaft 8 with universal joints 7, 7 interposed between a bracket 6 fixed to the machine frame 1 and the machine frame 1, and a steering gear 9 fixed to the lower end of the steering shaft 8. is meshed with the steered gear 3, and the input shaft 2 is connected to the sprocket 10 fixed to the upper end of the steering shaft 8 and the steering handle 11.
1 (see FIG. 2).
A chain 13 is stretched between a sprocket 12 fixed to an output shaft 22 of the motor, and the wheels 5 are steered by rotating the handle 11.

FIG. 2 is a longitudinal cross-sectional view of the first embodiment of the present invention, and FIGS. 3 and 4 are exploded views and cross-sectional views of the main parts thereof, respectively.

A shock absorber 20 is fixed to the bracket 6,
It also has a housing 23 that supports the input shaft 21 and the output shaft 22 through bearings so as to be rotatable but immovable in the axial direction. The housing 23 is divided into an upper housing half 24 and a lower housing half 25 to be fixed to the bracket 6, and a cylindrical sleeve 26 is tightly fitted and fixed to the inner wall of the lower housing half 25. ing. The sleeve 26 is made of steel and has a hardened cylindrical engagement surface 27 formed on its inner surface, and is press-fitted into the lower half portion 25 of the housing. The input shaft 2
1 and the output shaft 22 are arranged concentrically on the engagement surface 27, and at the end located inside the housing 23, a disc-shaped end plate 28, which extends in a plane perpendicular to the respective central axes, is provided. 29 are formed concentrically and integrally, and each end plate 28, 29 has a planar end surface 3 extending in a plane perpendicular to the respective central axis.
0 and 31 are formed to face each other in parallel with a predetermined interval.

As clearly shown in FIG. 4, the end surface 30 formed on the end plate 28 of the input shaft 21 has a surface perpendicular to the central axis X of the engagement surface 27 of the sleeve 26 (see FIG. at a position that is line symmetrical with respect to one diameter line AA passing through the central axis X, and from the central axis
Choose two points Y and Z separated by a distance T along
two short axes 3 having equal diameters whose central axis is an axis passing through the points Y and Z and parallel to the central axis X;
Plant 2,33. The short shafts 32 and 33 have their bases connected to holes 34 and 35 (third
(see figure), and the length of the protrusion from the end surface 30 is equal to or slightly shorter than the axial distance between the end surfaces 30 and 31.

As is particularly clear from FIG. 3, the end plate 29 of the output shaft 22 has a surface perpendicular to a diameter line passing through the central axis of the output shaft 22 at a part of the periphery of the end surface 31 thereof. A projection 37 with an abutment wall 36 projects in the axial direction. The top of the protrusion 37 is formed in a plane perpendicular to the central axis of the output shaft 22, and the protrusion length from the end face 31 is equal to or slightly less than the axial distance between the end faces 30 and 31. Considered to be short in length.

A center hole 3 is provided between the end surface 30 of the end plate 28 of the input shaft 21 and the end surface 31 of the end plate 29 of the output shaft 22.
Two steel rollers 4 of the same size are formed concentrically on cylindrical peripheral walls 40 and 41, respectively.
2 and 43, and insert the center hole 3 of one roller 42.
8 to the short shaft 32, and the center hole 39 of the other roller 43 to the short shaft 33, respectively.
The axial end faces of both rollers 42 and 43 are slidably disposed on the end faces 30 and 31.

A cylindrical hole 44 is bored in the protrusion 37 formed on the end plate 29 of the output shaft 22 at the center of the abutment wall 36 so as to have a central axis perpendicular to the wall 36 and in the radial direction. On the other hand, a leaf spring 4 is placed between the enlarged head 45 of the push pin 46 having an enlarged head 45 and the pin body.
7 is supported and fixed, and the push pin 46 is inserted into the cylindrical hole 44 so that the bottom wall of the hole 44 and the enlarged head 45 of the push pin 46
(or a leaf spring 47), a coil spring 48 is elastically installed between the leaf spring 47 and the roller 4.
The peripheral walls 40 and 41 of No. 2 and 43 are elastically installed. The leaf spring 47 has a rectangular shape in plan view, and the pin body of the push pin 46 penetrates in the plate thickness direction at the intersection of the diagonals and is fixed to the enlarged head 45, and has arcuate curved parts 49 at both ends. 50 is formed, and the curved portions 49, 50 press against the peripheral walls 40, 41 of the rollers 42, 43 with a required area, and the plate spring 47 and the spring 4
8, the rollers 42, 43 are urged away from the abutting wall 36. Further, at the tip of the enlarged head 45, the head 45 has a roller 42,
When contacting the peripheral walls 40 and 41 of 43, the peripheral wall 4
The rollers 42, 4 collide with the rollers 42, 4 with a predetermined area.
A braking surface 51 for braking 3 is formed.

The radius of the center holes 38, 39 of the rollers 42, 43 is larger than the radius of the short shafts 32, 33 by a dimension t, and within the range of this difference in radius, the rollers 42, 43 have a diameter larger than that of the short shafts 32, 33. 33, and the peripheral walls 40, 41 of the rollers 42, 43, respectively, are movable relative to the housing 23.
The rollers 42, 4 can abut against the cylindrical engagement surface 27 of the output shaft 22, and can abut against the abutment wall 36 formed on the end plate 29 of the output shaft 22 via a leaf spring 47.
The peripheral walls 40 and 41 of No. 3 are formed to have dimensions that allow them to abut each other.

Further, inside the housing 23, there is a nipple 5 screwed into the oil passage 52 of the lower half portion 25 of the housing.
Lubricating oil is sealed through 3, and at least the input shaft 2
The end plate 28 of the output shaft 2, the end plate 29 of the output shaft 22, and the mechanism existing between the end plates 28 and 29 are immersed in lubricating oil.

In the above-mentioned shock absorbing device, the short shafts 32 and 33 of the same radius are connected to one part of the input shaft 21 so that the steering force is equal when the steering wheel 11 is rotated in two directions, clockwise and counterclockwise. Rollers 4 of the same size are fixed at symmetrical positions with respect to the diameter line.
2 and 43 are fitted together, and the output shaft 22
Although one protrusion 37 was formed on the end plate 29,
The protrusion 37 may be formed in sections so as to provide abutment walls for the two rollers 42 and 43 at symmetrical positions with respect to one diameter line of the output shaft 22.

The operation of rotating the handle 11 of the shock absorber constructed as described above will be explained with reference to FIG. FIG. 5 is a cross section on the same plane as FIG. 4, and the input shaft 21 connected to the handle 11 is in the fifth
When the input shaft 21 is rotated counterclockwise in the direction of arrow P in the plane of the figure, the short shafts 32 and 33 fixed to the end plate 28 formed on the input shaft 21
The short shaft 32 is rotated by the roller 42.
The abutment wall 36 of the protrusion 37 of the end plate 29 formed on the output shaft 22 abuts against the center hole 38 at point B to move the roller 42 and leaf spring 47 against the elasticity of the spring 48. collide at point C, and the point C
The steering torque of the input shaft 21 is transmitted to the input shaft 21 as shown by the arrow Q, and the steering torque is transmitted to the output shaft 22 via the protrusion 37 . While the rotation of the input shaft 21 is being transmitted to the output shaft 22, the roller 42 is being transmitted to the engagement surface 27 of the housing 23 and sliding against the curved portion 49 of the leaf spring 47.
The other roller 43 is connected to the housing 2 with its peripheral wall 41.
3, the peripheral wall 41 of the plate contacts the peripheral wall 40 of the roller 42 at point D, or the central hole 39 contacts the short shaft 33 of the roller 42 at point E. Due to the elasticity of the spring 47, no load is applied, and the roller 43 is freely rotating. The short axis 33 reaches the contact point E with the center hole 39 of the roller 43 with a delay.

While performing a steering operation by rotating the handle 11 in the direction of arrow P in FIG. As shown by arrow R, a sudden load of clockwise rotation may be transmitted. When such a load is applied, the output shaft 22
Therefore, a torque as shown by arrow S is applied to the roller 42 via the protrusion 37 formed on the end plate 29. The roller 42 is pressed against the engagement surface 27 of the housing 23 by this torque and contacts the roller 43 in an attempt to transmit power in the opposite direction to the direction of the steering, and the roller 43 is moved against the elasticity of the leaf spring 47 and rotated around the center axis X. Try to rotate it counterclockwise. This rotation brings the peripheral wall 41 of the roller 43 into pressure contact with the braking surface 51 formed on the enlarged head 50 of the push pin 46,
A braking force based on the elasticity of the coil spring 48 is applied.

In this state, the peripheral wall 40 of the roller 42
is applied to the abutment wall 36 of the protrusion 37 of the output shaft 22 at point C, to the engagement surface 27 of the housing 23 at point F, and to the peripheral wall 4 of the other roller 43 at point D.
1, and the peripheral wall 41 of the other roller 43 is pressed against the engagement surface of the housing 23 at point G. Therefore, roller 4
At the contact point D of Nos. 2 and 43, sliding friction occurs because both rollers roll in the same direction.

As described above, the enlarged head 5 of the push pin 46
Since the braking surface 51 formed at zero applies a braking force to the circumferential wall 41 of the roller 43 based on the elasticity of the spring 48, a large frictional force is generated at the pressure contact point D of the roller 42 with the circumferential wall 40, and the roller 42 C, F, D
output shaft 22, housing 23,
A large frictional resistance will be generated between the roller 43 and the roller 43. Therefore, the rollers 42 and 43 are no longer able to rotate around the short axes 32 and 33 and roll against the engagement surface 27 of the housing 23, and the rollers 42 and 43 are no longer able to rotate on their own axis around the short axes 32 and 33, respectively, and are unable to rotate in the direction indicated by the arrow S that is applied to the output shaft 22 due to the disturbance. The torque is consumed by the frictional resistance at points C, F, D, and G and the braking force by the braking surface 51 of the push pin 50, and is not transmitted to the input shaft 21.

When the torque applied to the output shaft 22 in the direction of arrow S due to disturbance becomes even larger, the coil spring 48 is further compressed to tighten the peripheral wall 4 of the roller 43.
1 comes into pressure contact with the abutting wall 36 formed on the output shaft 22 side via the leaf spring 47 at point H, which applies frictional resistance to the roller 43 and pushes the peripheral wall 40 of the roller 42 towards the push pin 46. It is brought into pressure contact with a braking surface 51 formed on the enlarged head 50 to apply strong braking force to the rollers 42 and 43 to absorb torque caused by disturbance.

FIG. 7 shows a second embodiment of the present invention, and is a sectional view taken along the same section as FIG. 4. This embodiment differs from the configuration shown in FIG. 4 of the first embodiment only in that the shape of the leaf spring is changed and it also functions as a braking surface formed on the enlarged head of the push pin. Since the parts shown in FIG.

The leaf spring 147 of the second embodiment has braking parts 151 and 1 having two sides of equal length surrounding the apex angle by a plate-shaped spring member.
51 and is fixed to the tip 150 of the push pin 146 by a base 152 forming the other side.
and the bottom wall of the cylindrical hole 45.
8 is elastically installed, and the braking portions 151, 151 are configured to come into pressure contact with the peripheral walls 40, 41 of the rollers 42, 43.

According to this embodiment, when the handle 11 is rotated, the rollers 42 and 43 directly collide with the abutment wall 36 of the protrusion 37 formed on the output shaft 22 to output steering force from the input shaft 21. At this time, the braking portion 151 of the leaf spring 147 contacts only the roller 42 in the case of rotation operation in the direction of arrow P, but the pressure contact force is small. On the other hand, when torque in the direction of arrow R due to disturbance is transmitted to the output shaft 22, both rollers 42 and 43 are
1 and 151 to compress the coil spring 48, apply braking force to both rollers 42 and 43, and buffer the torque caused by the disturbance similar to that described based on the first embodiment.

[Operation and effects of the invention]

As described above in detail based on the embodiments, in the shock absorber of the present invention, the ends of the input shaft and the output shaft are rotatably disposed concentrically on the cylindrical engagement surface formed on the housing. an end plate having an end face extending in a plane perpendicular to the central axis of the engagement surface; Two short shafts are installed at positions that are line symmetrical and spaced from the central axis in the radial direction with respect to the diameter line, and rotating annular rollers that are loosely fitted in the center holes on each of the short shafts. The roller is slidably positioned between the end faces of the input shaft and the output shaft, and the end plate of the output shaft has a roller that is symmetrical with respect to a diameter line passing through the central axis of the output shaft. An abutting wall that abuts the peripheral wall of the roller is formed at a position radially distant from the central axis with respect to the diameter line, and the output shaft has an abutting wall that can contact the peripheral wall of the roller over a predetermined area. A braking member is disposed in the diametrical direction of the output shaft to urge the rollers away from the abutting wall, and the two rollers engage the engagement surface of the housing and the output with their peripheral wall portions. Since it has an outer diameter and an inner diameter that can abut against the abutting wall of the shaft and abut against each other, when rotational torque is transmitted from the input shaft to the output shaft side, the input Among the short shafts installed on the end plate of the shaft, the short shaft on the preceding side in the rotation direction is loosely fitted to the short shaft.A first roller is formed on the end plate of the output shaft. The second roller abuts against the abutting wall to transmit rotational torque to the output shaft, and at this time, the second roller abuts the first abutting wall.
Even if it comes into contact with the roller or the engagement surface of the housing, no frictional resistance that would impede the transmission of rotational torque is generated, so that the rotational torque is transmitted smoothly.

However, when a torque that resists the rotational torque is applied to the output shaft side due to a disturbance, the torque is transmitted to the second roller via the first roller that abuts the abutment wall, This second roller is brought into pressure contact with the engaging surface of the housing and the braking surface of the braking member, and the braking force of the braking member causes the first roller that is abutting against the abutting wall to be brought into contact with the abutting wall and the braking surface of the housing. The output shaft is brought into strong pressure contact with the mating surface and the second roller, and the output shaft is fixed to the housing by the braking force between the second roller and the braking member and the frictional resistance between the first and second rollers. This buffers the torque due to disturbances applied to the input shaft and prevents it from being transmitted to the input shaft.

Further consideration of the buffering of torque based on the above-mentioned disturbance reveals that the two rollers contact each other due to the torque caused by the disturbance (Fig. 6D), and the point where the two rollers each contact the engagement surface of the housing. The triangle formed by the points (F, G in Fig. 6) is located at a position that does not include the central axis of the engaging surface (X in Fig. 6), and is formed on the output shaft at least on the peripheral wall surface of the first roller. It can be seen that the above-mentioned buffering effect is achieved when conditions are met in which the abutment walls abut and the braking member disposed on the output shaft elastically abuts against the circumferential wall surface of the second roller to apply a braking force. Therefore, the diameter of the peripheral wall of the roller is smaller than the radius of the engaging surface of the housing, and the position of the abutting wall is determined by the difference between the diameter of the peripheral wall of the roller and the diameter of the center hole and short axis of the roller. It must be determined with consideration.

Note that the present invention is not limited to the shock absorbing device for the steering device of an industrial vehicle as shown in the embodiment, but is also applicable to the manual winding of a wire that is tensioned when a heavy object is suspended, such as a wire for stretching a tennis net. It can also be applied to shaft shock absorbers, etc.

[Brief explanation of the drawing]

Fig. 1 is a front view of a reach-type forklift steering device suitable for implementing the shock absorber of the present invention, Fig. 2 is a longitudinal cross-sectional view of an embodiment of the present invention, and Fig. 3 is an exploded view of the portion with the housing removed. Fig. 4 is a cross-sectional view along the line of Fig. 2 with the housing removed; Figs. 5 and 6 are explanatory diagrams of its operation; Fig. 7
The figure is a cross-sectional view similar to that in FIG. 4 in another embodiment of the present invention. In the figure, 21 is the input shaft, 22 is the output shaft, and 23 is the input shaft.
is a housing, 27 is an engagement surface thereof, 28, 29 are end plates, 32, 33 are short shafts, 36 is an abutting wall, 42,
43 is a roller, 46 is a push pin, 51 is a braking surface, and 151 is a braking portion.

Claims (1)

[Claims] 1. Provided between an input shaft to which a rotational operating force is applied and an output shaft to which the rotational operating force is transmitted and operated, the torque of the input shaft is smoothly transmitted to the output shaft, and , a device for buffering the load transmitted from the output shaft to the input shaft when a load caused by a disturbance is transmitted to the output shaft, the input shaft and the housing having a cylindrical engagement surface formed on the inner wall. an end of the output shaft is disposed concentrically with the central axis of the engagement surface and is rotatably supported by the housing, respectively; end plates each having an end face extending in a plane perpendicular to the input shaft are formed, and the end faces are opposed to each other at a predetermined interval; Two short shafts are erected in parallel to the central axis of the input shaft at positions that are symmetrical about one diameter line and radially distanced from the central axis of the input shaft with respect to the diameter line. , two annular rollers that are loosely fitted to the short shafts through their center holes are rotatably and slidably inserted into a space formed on the input shaft and the output shaft where the end faces face each other; The end plate formed on the output shaft is provided with the above-mentioned at a position that is line symmetrical with respect to a diameter line passing through the central axis of the output shaft and is distanced from the central axis of the output shaft in the radial direction with respect to the diameter line. A braking member is configured to form an abutment wall that abuts against the peripheral wall of the roller, and is capable of abutting against the peripheral wall of the roller over a predetermined area. The two rollers are disposed so as to be pushed in a direction away from the mating wall, and the two rollers abut against the engaging surface of the housing and the abutting wall of the output shaft at their peripheral wall portions,
A shock absorbing device for a rotary operation shaft, characterized in that it has an outer diameter and an inner diameter that can abut each other. 2. The cylindrical engagement surface is formed on the inner surface of a cylindrical sleeve formed separately from the housing, and the sleeve is fixed to the housing. The shock absorber for the rotary operation shaft according to item 1. 3. The braking member is formed on a push pin supported by the end plate so as to be slidable in the direction of the central axis, with the central axis disposed in the diametrical direction of the one of the output shafts, and the sliding rod and the end plate are connected to each other. 2. The shock absorbing device for a rotary operation shaft according to claim 1, further comprising a spring that springs in the diametrical direction. 4. The braking member is a leaf spring that is fixed to the sliding rod at its center and has curved portions on both sides that abut against the peripheral walls of the two rollers,
4. A damping device for a rotary operation shaft according to claim 3, wherein a braking surface that can abut against the peripheral walls of the two rollers is formed at the tip of the push pin.