JPS6116173A - Steering system for car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering system for a four-wheeled vehicle.

In a typical vehicle, two at one end (usually the rear end)
The wheels are mounted rotatably but not steerable, and the wheels at the other end (usually the front end) are mounted rotatably and steerably.

When steering a vehicle to the left or right, both front axles are steered in the same direction, causing the vehicle to turn around a point on an extension of the rear wheel axis.

This point is far from the vehicle and increases its turning radius. In order to obtain high maneuverability, it is necessary to set the turning radius of the vehicle to zero so that the vehicle turns around the left rear wheel when turning left, and around the right rear wheel when turning right.

In this case, in order to avoid dragging or slipping the front wheels while the vehicle is turning, the amount of steering of both front axles must be different. Ideally, each front wheel should be steered at right angles to a line from the center of the turn to the center of the front wheels.

In conventional steering mechanisms using lever arms, bell cranks, tie rods, or links, the steering force increases as the wheels are steered from neutral.

This steering force becomes extremely large as the turning radius approaches zero.

In view of the above-mentioned circumstances, the present invention makes it possible to make the turning radius zero by varying the amount of turning of both steered wheels, and also prevents the tires from being dragged too much or the single steering force from becoming excessive. The purpose of the present invention is to provide a steering system for vehicles that has improved performance.

The present invention has been made to achieve the above object without causing the above-mentioned problems.

SUMMARY The steering system for a four-wheeled vehicle of the present invention includes a steering column for each front wheel, an eccentric sprocket is provided on these columns, a drive sprocket rotated by a manual steering member is provided, and a steering column is provided between the eccentric sprocket and the drive sprocket. It is made by passing a chain means over the.

In the present invention, it is preferable to add a chain tensioning means for maintaining the chain means at a predetermined tension even if the distance from the eccentric sprocket to the driving sprocket changes during steering.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

The drawing shows a preferred embodiment of the invention, in which the work trolley 1o comprises a wheeled base 11 and is provided with a vertical mast I2 on which a work platform 18 is mounted for vertical movement. A suitable power mechanism is provided to raise and lower the workbench 18 relative to the base 11.

A right front wheel RFW, a left front wheel LFW, and a right rear wheel RRW and a left rear wheel LRW are provided on a base 11. The rear wheels are mounted rotatably around the horizontal axis and cannot be steered around the vertical axis. The front wheels RFW and LFW are mounted rotatably around the horizontal axis and can be steered around the vertical axis. For example, the second
As shown in the figure, the left front wheel LFW is rotatably attached to the bracket 16.

The vertical support 17 is fixed to the bracket) 16, and its axis "0"
LFW is aligned with the vertical axis MCLFW of the left front wheel, and the support column 17 is rotatably journal-beared in a bearing 18 attached to a seven-frame frame of the base. Similarly, right front wheel RFW
is rotatably attached to a bracket 21, and its column 22 is journal-supported in a bearing 28. By aligning the vertical axis of the strut 22 with the vertical axis of the right front wheel RFW and rotating the strut 22 around the vertical axis, the right front wheel can be steered.

Fluid motors 26 and 127 are attached to the wheel brackets 16 and 21 to drive the front wheels. fluid pumps, reservoirs,
Conventional power sources, including batteries, are mounted within the midsection 28 of the base 11 as usual.

The steering system of the present invention has right and left sprocket R.
WS and LWS are fixedly attached to a column 22.17, and a drive sprocket DS is rotatably attached to a column 29, and this column is arranged approximately at the center of the base frame 19. The drive sprocket DS has a sprukerato member 81 arranged coaxially above and below.・It is composed of 82 and is connected to each other so that they move together. First standard roller chain 8
8 on the upper sprocket member 81 and the right sprocket RWS, and the second standard roller chain 84 on the lower sprocket member 82 and the left sprocket LWs.

Chains and sprockets are preferably used, but wire lobes, toothed belts, their extension means and pulleys may be used instead.

27t) 77) Fix the shaft 86 to the DS and extend it upward into the vertical sleeve 87, which is rotatably mounted on the workbench 18. Shaft 86 and histogram 87 have non-circular cross-sections to allow movement of platform 18 and sleeve 87 in a direction perpendicular to axis 86 while maintaining a driving connection therebetween.

A handle 88 is fixed to the upper end of the sleeve 87, allowing an operator to handle the sleeve 87, shaft 86 and drive sprocket.
The work cart 1o can be steered by rotating the DS.

As shown in Figures 2 and 8, the left sproget) LW
S is installed in the support column 17 so that its center ○Lw8 is eccentric from the vertical axis OLFW of the left front wheel toward the driving sprocket DS.
Install eccentrically on top. Similarly, the right sprocket) RWS
is eccentrically attached to the support post 22 so that its center 0RWS is eccentric from the vertical axis 0RFW of the right front wheel toward the drive sprocket.

A first chain tensioning means 4o is provided to allow the center of the right sprocket (RWS) to move in the direction of force towards or away from the axis of the drive sprocket (DS) while keeping the chain 88 suitably tensioned. Chain tensioning means 40
The arm 41 is rotatably mounted on the support column 42 and extends in the direction of the chain 88. The arm 41 is pivotally connected to the link 44 of the chain 88 at 48.

Similarly, a second chain tensioning means 46 is provided for the chain 84, and its rigid arm 46 is rotatably attached to the support 47, and the link 49 of the chain 84 is attached at 48.
It is pivoted to.

FIG. 4 shows that the operator turns the handle 88 60 degrees counterclockwise in the direction of the hour hand.
Indicates the wheel position when turning to the maximum left. Since it is desirable for the work truck 10 to turn around the left rear wheel LRW, the steering system steers the front two wheels so that they are both perpendicular to the through line leading to the respective left rear wheel. The left front wheel is therefore steered 90 DEG about its vertical axis. Also, if the work truck IO is of a particular size, the front right wheel will be steered 66° to the left about its vertical axis.

As shown in FIG. 5, when the handle 88 is rotated counterclockwise, the drive splot is rotated 60 degrees counterclockwise, and the chain 88 is driven in the direction of the arrow. chain 88
The pulling force causes the right sprocket RWS to rotate counter-clockwise through the portion 88b with the link 44 about its center, i.e. around the vertical axis of the right front wheel (CRFW), thereby causing the sprocket center CRWS to rotate in the direction of the driving sprocket.
+ Far away from D・S. Such movement of the sprocket turns the right front wheel 56 degrees to the left and steers it.

At the same time, the 60° counterclockwise rotation of the drive sprocket (DS) applies a tensile force to the chain 84 (the chain portion 84aE facing the portion 84b having the link 49), causing the left sprocket (LWS) to rotate at its rotation axis 1! Rotate around 0LFW, this will center the left sprocket 0LWS
is also far away from the drive sprocket DS. This movement causes the left front wheel to be steered to the left by 90 degrees.

Figures 6 and 7 show the state when the steering wheel 88 is rotated from the neutral position (position where both front widths are not steered) up to 60 degrees in the direction of the hour hand, and at this time the vehicle moves around the right rear wheel. to make a maximum right turn. Drive sprocket DS 6 due to this
At 0° rotation, the chain portion 88a is pulled against the right sprocket, causing it to rotate 90° about its axis of rotation 'l'i'RFW.At the same time, the drive sprocket D
S applies a tension of 1 to the chain portion a4b and rotates the right sprocket LWS by 56° around its axis 0LFW.

8 to 11 show the operating principle of an eccentric sprocket steering system configured to obtain a desired left and right front wheel steering angle difference depending on the rotational direction of the drive sprocket. Each of these four drawings shows the left sprocket LWS or right sprocket RWS, and the chain portion 88a or 84a.
The solid line indicates the neutral (non-steering) position, the dotted line indicates the 90° counterclockwise rotation (left turn), and the one-dot chain line indicates the 90° counterclockwise rotation.
This is when the hour hand rotates 0° (clockwise rotation). In each of these figures, the ratio of the circumference of the sprocket LWS or RWS to the eccentricity of the sprocket (distance between the center of the sprocket and the axis of rotation) was 20:1.

FIG. 8Gk shows a steering system in which a line passing through the center OLws of the left sprocket and the axis of rotation CLFW coincides with a line passing through the axis of rotation OLFW and the rotation of the drive sprocket DS. For simplicity, the chain part 84a is set so that the left sprocket LWS is neutral (N
)' position, 90° left (L) position, or 90° right (R) position, parallel to the sprocket center-to-center line.

Also, any point A on the chain portion 84a is assumed to be at the AN position when the sprocket LWS is at the neutral position. Points TN, TL, and TR are neutral and 90° left, respectively.
Chain part 8 against sprocket at 90° right position
4a shows the contact point.

When the drive sprocket DS is rotated counterclockwise, the chain portion 84& is pulled against the drive sprocket, causing the sprocket LWS to rotate counterclockwise about its axis of rotation 0LFW. When the sprocket is rotated 90 degrees, the sprocket center 0LWS moves from point N to point N. Similarly, the contact points of the chain portion 84a are from point TN to point T.
Move to L. A 90° rotation of the sprocket will cause the chain to move forward by an amount of π (d is the diameter of the sprocket), and this amount of payout is equal to five times the amount of sprocket eccentricity e. However, the contact point is TN.

point A on the chain portion 84a goes straight toward the drive sprocket (from AN to AL), and the amount of the distance from the drive sprocket to the contact point TL is πd/4. less than the distance increase. In this example, the distance increase (TL
-TN) is equal to the sprocket eccentricity e. Therefore,
If the linear movement of the chain section 84a towards the drive sprocket is equal to (πd/4-e), then the sprocket)
A 90° left rotation of the LWS (90' left steering of the left front wheel) occurs. If the ratio of sprocket circumference to eccentricity is 20:4, the linear movement of chain portion 84a due to a 90° counterclockwise rotation is equal to 4e. The amount of rotation of the drive sprocket D required to achieve such linear movement of the chain portion 84a naturally varies depending on the diameter of the drive sprocket. When the sprocket is rotated in the hour hand direction (to the right) by tension from chain section 84b (not shown in this figure), chain section 84a is wrapped around the sprocket and the point on the chain is moved away from the drive sprocket. Karu. The sprocket LWS winds the chain by a length of π (M4, where d is the sprocket) by rotation in the direction of the hour hand by fl-θ°. At the same time, the contact is from TN to TR.
The sprocket moves away from the drive sprocket by an amount of eccentricity e. Therefore, when the left sprocket (LWS) rotates in the hour hand direction, the amount of linear movement of the chain portion +34a (from AN to AL) is (πa/is + e). In this example, this amount of movement is equal to 60.

What is important here is that the amount of rotation in the direction of the hour hand (for example, 9
The amount of rotation of the drive sprocket DS in the hour hand direction to produce a rotation angle of 0°) is greater than the amount of counterclockwise rotation of the drive sprocket DS to produce the same amount of counterclockwise rotation of the sprocket. In the configuration shown in Figure 8, the left sprocket LW
The ratio of the amount of rotation in the direction of the hour hand to the amount of rotation in the direction of the counter-hour hand of drive sprocket DS to cause the rotation of S in the direction of the hour hand (to the right) or in the direction of the counter-hour hand (to the left) by 90° is 6e:4e.
or 1.5: equal to 1. Similarly, when rotating the drive sprocket DS by the planned amount in both directions, the amount of rotation of the LWS in the counter-hour direction (left direction) is
rightward) is larger than the amount of rotation.

The amount of eccentricity of the sprocket greatly affects the ratio of left rotation to right rotation of the sprocket when the driving sprocket is rotated by a predetermined amount. For example, in Fig. 8, if the amount of eccentricity of the LWS is half of the above value, the amount of chain movement (π&+-e) when turning 60 degrees to the left is 9e, and the amount of chain movement when turning 90 degrees to the right (πV4
+ 6) becomes lle. Therefore, in order to rotate the left sprocket by 90 degrees to the right or left, the ratio of the amount of rotation of the driving sprocket in the counter-clockwise direction to the amount of rotation in the direction of the hour hand is 118.
: 9e or 1.22 : Reduced to 1.

FIG. 9 shows a system in which the right sprocket RWS driven by the drive sprocket DS and the chain are mirror images of the case in FIG. 8. According to the same analysis as described above, when the drive sprocket DS and the right sprocket (RWS) rotate in the counterclockwise direction (to the left) and the rotation amount of the right sprocket is 90 degrees, the point on the chain portion 88a becomes AN'. The sprocket moves from the drive sprocket DS to AL, and is further away from the drive sprocket DS by (πd/+ + 6.;), where d,
e is the diameter and eccentricity of the right sprocket, which is the same as the left sprocket, which is located in a mirror-symmetrical position. Similarly, when the right sprocket rotates 90 degrees in the direction of the hour hand (to the right), point A moves from AN to AR and approaches the drive sprocket by (πd/4-e). In the case of the sprocket RWS shown in Fig. 9, the drive sprocket for rotating the sprocket RWS by 90° in the hour hand direction (rightward direction) or counterclockwise direction (leftward direction)) The ratio is the reciprocal of that in the case of LWS, that is, (ycd/4-e) : (yr
d/4+6) or 1:1.5.

Thus, in the steering system using sprockets arranged mirror-symmetrically as shown in FIGS. 8 and 9, the drive sprocket DS is moved counterclockwise to the chain portion +34a.
When the left sprocket LWS is rotated by an amount that is pulled by a distance (πaA−e), the left sprocket LWS is rotated 90° to the left. At the same time, the chain portion 88b is also moved by the same amount ff1 (πCV4-8), and with the right sprocket, it is rotated to the left by a smaller angle. Conversely, when the drive sprocket is rotated by the same amount from the neutral position, the chain portions 88a, 84b will rotate at (πd7
4-6) [11] and rotate the right sprocket to the right by 90 degrees and the left sprocket to the right by a lesser amount.

Figure 10 shows a configuration similar to Figure 8, except that the line passing through LFW and 0LWS is at an angle of -45° with respect to the line passing through 0LFW and ODs at the neutral position of the left sprocket. When the sprocket LWS is rotated 90 degrees counterclockwise (to the left), the contact TN moves away from the drive sprocket by eσ and reaches TL.Therefore, the point A on the chain moves from AN to AL (πd/4-ei ). When the left sprocket LWS rotates 90° to the right, the contacts TN and TR are located equidistant from the drive sprocket, and the chain section 84a moves by (πd/4). When the left sprocket LWS rotates 90° to the right, the chain portion 84a moves by (πd/4). The ratio of rotation of the drive sprocket DS in the direction of the hour hand to rotation in the direction of the hour hand in order to rotate the drive sprocket to the right or left is πd-20
6, (πC1/4) : (πd/4−
e-if), that is, 1.894:1.

Figure 11 G line 0LFW -0LWS and line 0LFW -
The configuration is shown when the angle formed by CDS force 1 is +80°. As described above, when the sprocket LWS rotates 90 degrees to the left, the linear movement amount of the chain portion 84a is πd/4, which is smaller than the amount of increase in distance from the drive sprocket when the contact point moves from TN to TL. Similarly, when LWS is rotated 90 degrees clockwise, chain part 8
The linear movement amount of 4a is πV4, and the contact points 'I'L, TN
equal to the increase in distance from the drive sprocket by 1. In the case of Fig. 11, left sprocket LW
(Driving subrocket for rotating S by 90 degrees to the right or left) The ratio of the rotation of the hour hand to the counterclockwise rotation of the DS is approximately 1.87:1.

When the angles formed by the straight lines 0LFW-0LWS and 0LFW-CDS are made different, the amount of chain movement and the rotation ratio of the drive sprocket will be different. However, sprockets)
If the center CLWS of the LWS is moved closer to the center ODs of the drive sprocket than the center of rotation 0LFW in its neutral position, it will be the left sprocket).The drive sprocket for rotating the LWS by 90 degrees to the right or left) will rotate the DS in the counterclockwise direction. The ratio of rotation in the direction of the hour hand is 1 or more. This ratio is maximum in the case of FIG. 8. Sprocket) LWS
Its center CLWS is the rotation center 0LF at the neutral position of
If you move the sprocket further away from the center ODS of the drive sprocket than W, the sprocket will be 90'. The ratio of the rotation of the drive sprocket in the counterclockwise direction to the rotation in the direction of the hour hand for clockwise or counterclockwise rotation is 1 or less. The latter configuration is unsuitable for use in the steering system of the present invention, and the reason is that, contrary to the requirements, the left wheel steering amount when turning left is the right wheel turning amount (the opposite when turning right).
This is because there will be less.

In the case of a steering system that turns the vehicle around the rear wheels, the steering ratio between the front wheels is determined by the distance between the four wheels. For example, in the vehicles shown in Figures 1 to 7, the above ratio is 90°.
=56° or 1.61:1.

The diameter of the sprocket is determined as required. '130LFW -CLWS and 0 at neutral position of left sprocket
The angle formed by LFW-ODS and the amount of eccentricity of the sprocket are such that when the drive sprocket is rotated by the same angle from the neutral position toward the hour hand or counterclockwise, the left sprocket is rotated 56 degrees to the right and 90 degrees to the left. Decide as follows. The amount of rotation of the drive sprocket to obtain maximum steering is determined by the relationship between the diameters of the drive sprocket and the sprocket. One half of the steering system determines the other half, since the two halves are mirror images of each other.

When manufacturing the steering system, suitable chain tensioning means 4 for each eccentric sprocket LWS, RWS are required.
It is necessary to set 0. As is clear from the foregoing, when the drive sprocket DS is rotated in the direction of the hour hand, the left sprocket LWS is rotated by the tension of the chain portion 84b. If the chain section 84b is elastically biased into a tensioned state, for example the state shown in FIG. You can keep it tense without rotating it.

In a system as shown in FIGS. 1 to 7, where the distance between the sprocket and the drive sprocket increases equally during rotation in both directions from the neutral point, the stiff arm pivoted on the strut 47 and the chain link 49; , can provide a reliable, non-compressible means of maintaining chain tension as the sprocket and drive sprocket center-to-center distances change. The eight positions of pivot point 48 in FIGS. 8, 5, and 7 define a circle. The center of this circle is located at the post 47 and the radius of this circle determines the length of the arm 46.

As is clear from the foregoing, the present invention has the advantage of keeping the steering force constant. The steering force of the outer wheel is
It decreases as the inside wheel steering force increases.

Brief explanation of the front screen Fig. 1 is a side view of a working trolley equipped with the steering system of the present invention, Fig. 2 is a front view thereof, Fig. 8 is a sectional view taken along line 8-8 in Fig. 1, Fig. 4 and Figure 6 is a route map showing the wheel steering situation of the work trolley at maximum left turn and maximum right turn, respectively. Figures 5 and 7 show the steering system at maximum left turn and maximum right turn, respectively. The sectional view corresponding to FIG. 8 shown in FIG. 8 and FIGS. 8 to 11 are diagrams of the operating principle of the steering system of the present invention.

lO...Work trolley 11...Wheeled pace 12...Vertical mast 18...Work platform RFW...Right front wheel LFW...Left front wheel RRW...Right rear wheel LRW...Left rear wheel Wheel 16...Wheel bracket 17 i--Vertical support 18...Bearing 19...
Pace frame 21...Wheel bracket 22...
・Strut 28...Bearing 26, 27...
・Fluid motor 29...Strut DS...Drive sprocket 31.32...Sprocket member RWS...Right sprocket LWS...Left sprocket 88.84...Chain 86...Shaft 87
...Vertical sleeve 88...Handle 40.4
5...Chain tensioning means 41.46...Rigid arm 42.47...Struts 43, 48...Pivot point 49...Chain link.

Patent Applicant Up-right Inconsolidated Drawings? 'r-2 (Contents: 2 No changes) FIG
8 FIG 9 FIG
OFIGl1 Procedural amendment (method) % formula % 1. Indication of the case 1982 Patent Application No. 135383 2. Name of the invention Vehicle steering system 3. Person making the amendment Relationship to the case Patent applicant

Claims (1)

[Claims] 1. A substantially horizontal frame, first and second wheels provided at one end thereof, and eighth and fourth wheels provided at the other end,
A steering system for a vehicle in which first and second wheels can be steered around individual vertical axes, comprising: first and second struts attached to the frame so as to be rotatable around their own axes; means for steering a wheel about its vertical axis in response to rotation of said first strut; and means for steering said second wheel about its vertical axis in response to rotation of said second strut. means for rotating the first and second struts in one direction from the neutral position in response to movement of the steering member in either direction from the neutral position; The amount of rotation of
In addition, when the steering member is moved from the neutral position to the other direction, the first and second columns are rotated from the neutral position to the other direction, and the rotation amount of the first column is made larger than the rotation amount of the first column. A steering system for a vehicle, comprising: a coupling means whose rotation amount is smaller than the amount of rotation of the column. 2. The connecting means includes: a first sprocket that is fixed to the first strut so as to rotate therewith, and whose center is offset from the axis of the first strut; and a first sprocket that is fixed to the second strut so as to rotate together with the sprocket, and whose center a second sprocket that is eccentric from the axis of the second strut; a drive sprocket that is coupled to the steering member and rotates in response to the movement of the steering member;
Sprocket and drive sprocket, and when the drive sprocket is rotated in one direction from the neutral position, in response to this, the first and second sprockets are rotated in one direction from the neutral position, and the drive sprocket is rotated in the opposite direction from the neutral position. a steering system for a vehicle according to claim 1, further comprising chain means configured to rotate the first and second sprockets in opposite directions from the neutral position in response to the rotation in the direction of the steering wheel; . 3. The vehicle steering system according to claim 2, wherein the connecting means is provided with means for keeping a chain tensioned around both sprockets and the driving sprocket during rotation in both directions. 4. At the neutral position of the drive sprocket, the center of the first sprocket is closer to the axis of the drive sprocket than the axis of the first support, and the center of the second sprocket is closer to the axis of the drive sprocket than the axis of the second support. A vehicle steering system according to claim 2. 5. The drive sprocket is composed of a first and a second coaxial sprocket member, which are connected to each other so as to rotate together, and the first chain is passed around the first sprocket and the first sprocket member, and the second sprocket and the second sprocket member are connected together. The vehicle steering system according to claim 2, wherein a second chain is stretched around the second sprocket member. 6. At the neutral position of the driving sprocket, the center of the first sprocket is located closer to the axis of the driving sprocket than the center of the first strut, and the center of the second sprocket is closer to the axis of the driving sprocket than the center of the second strut. , the coupling means further includes a first chain tensioning means for maintaining the first chain in tension about the first sprocket and the first sprocket member while rotating the first sprocket in one direction from the neutral position; 6. A vehicle steering system according to claim 5, further comprising second chain tensioning means for keeping the second chain tensioned around the second sprocket and the second sprocket member during rotation in one direction from the position. 7. The first chain tensioning means is provided with a first rigid arm, a means for pivotally connecting one end thereof to the frame, and a means for pivotally connecting the other end of the first rigid arm to the first chain; The chain tensioning means includes a second rigid arm, means for pivotally connecting one end thereof to the frame, and a second rigid arm.
7. The vehicle steering system according to claim 6, further comprising means for pivotally connecting the other end of the rigid arm to the second chain.