Torsion bar

Abstract

To provide a torsion bar with high versatility, capable of simplifying its structure and saving a space.SOLUTION: A torsion bar is provided with an inner rod having circumferential torsional elasticity, an outer rod including the inner rod and having circumferential torsional elasticity, and a connection part that fixes and connects the inner rod and the outer rod at an axial center part, and at both axial end parts of the inner rod and outer rod, connection parts to an object to which elasticity is applied are provided. Between the inner rod and outer rod and on the axial end part side, a restriction part is provided which allows relative axial rotation while restricting relative radial movement of the inner rod and outer rod.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a torsion bar having a multi-axis configuration. [Background technology]

[0002] In a four-wheeled vehicle, the difference in load between the left and right sides results in a stroke difference, and an excessive stroke difference causes the vehicle body to tilt, impairing steering stability. An independent suspension with a stabilizer is a mechanism that limits the stroke difference that causes the difference and improves the performance of sports driving while maintaining a soft ride. A stabilizer is another name for a torsion bar. A simplified version of this is the torsion beam suspension, which is currently the most widely used system for the rear wheels of four-wheeled passenger vehicles. (Patent Document 1) A torsion beam suspension has a structure in which a suspension mechanism with a coil spring is provided at each of two separated points, and the two suspension mechanisms are connected by a torsion beam, so that it has a suspension mechanism that receives the load of the two separated points or provides elastic force to each of them, and a stabilizer function that resists the phase difference between the two separated points. Although it is somewhat simpler than an independent suspension, it still requires a large installation space.

[0003] Also, there are known add-on tables used by passengers sitting in the rear seats of vehicles. As can be seen from the product names such as seatback table, these have a simple structure that is simply attached to the seat back, and are insufficient to provide a table with a full load capacity that can meet the needs of recent outdoor activities, sleeping in a car, etc. In order to fix a high load-bearing table with a single fixing structure regardless of the type of vehicle used, it is effective to support it by elastically bracing it between the backrest of the front seat and the floor surface of the rear seat, but it has been difficult to configure this fixing device so that it does not get in the way at the feet of passengers sitting in the rear seat and has a relatively strong fixing force. (Patent Document 2) [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6014136 [Patent Document 2] Design No. 1752187 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a highly versatile torsion bar that uses a single torsion bar to combine a suspension mechanism that receives loads from two spaced apart points or provides elastic forces to each of the points, and a stabilizer function that resists the phase difference between the two spaced apart points, thereby simplifying the structure and saving space. [Means for solving the problem]

[0006] In order to solve the above problems, the torsion bar of the present invention has a first feature in that it comprises an inner rod having a torsional elastic force in the circumferential direction of the axis, an outer rod that contains the inner rod and has a torsional elastic force in the circumferential direction of the axis, and a connecting portion that fixes and connects the inner rod and the outer rod at the axial center, and connecting portions are provided at both axial ends of the inner rod and the outer rod to an object to which an elastic force is applied.

[0007] A second feature is that a regulating portion is provided between the inner rod and the outer rod, on the axial end side, which regulates relative radial movement between the inner rod and the outer rod while allowing relative rotation in the axial direction.

[0008] A third feature is that the regulating portion is provided immediately adjacent to a journal portion that positions and supports the outer rod. Effect of the Invention

[0009] The torsion bar of the present invention comprises an inner rod having torsional elasticity in the axial direction, an outer rod containing the inner rod and having torsional elasticity in the axial direction, a connecting portion that fixes and connects the inner rod to the outer rod at the axial center, and connecting portions are provided at both axial ends of the inner rod and the outer rod to an object to which elastic force is applied.By doing so, a mechanism having an elastic force for applying or receiving a load to two spaced apart points and an elastic force for resisting the phase difference between the two spaced apart points can be completed with a configuration around the axis of a single torsion bar, which not only simplifies the configuration of the mechanism and saves space, but also provides a highly versatile torsion bar.

[0010] In addition, a regulating portion is provided between the inner rod and the outer rod and at the axial end portion, which regulates the relative radial movement between the inner rod and the outer rod while allowing relative rotation around the axis.Therefore, when viewed in axial cross section, the inner rod and the outer rod, the connecting portion located in the center, and the regulating portion located at the axial end portion can form a closed rectangular shape, which allows for sufficient torsion tolerance as a torsion bar while also providing a strong axial structure that regulates radial distortion.

[0011] Furthermore, by arranging the regulating portion so that it is overlapped immediately adjacent to the support portion that positions and supports the outer rod, the support portion, which is subjected to a large force, can be reinforced by the regulating portion.Furthermore, when setting the strength of the outer rod, there is little need to take into consideration the strength of the support of the outer rod, which increases the freedom to set the biasing torque of the outer rod and makes it easier to set the strength of the entire torsion bar and the torsional elastic force. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1A is an axial cross-sectional view of a torsion bar according to the present invention, FIG. 1B is an axial cross-sectional view of a torsion bar in which a regulating member has a ball bearing structure, and FIG. 1C is an axial cross-sectional view showing an embodiment in which an inner rod and an outer rod are connected by a spline joint. [Diagram 2] FIG. 1 is a plan view showing a typical hinge structure. [Diagram 3] FIG. 13 is a plan view showing a hinge structure using a coil spring as a biasing means. [Figure 4] FIG. 11 is a plan view showing a hinge structure using a torsion bar as a biasing means. [Diagram 5] FIG. 11 is a plan view showing a hinge structure in which the torsion bar has a double rod structure. [Figure 6] 1 is a table showing formulas showing the relationship between the shape of a torsion bar and the torque per torsion angle. [Figure 7] FIG. 1 is a plan view showing a hinge structure employing a torsion bar according to the present invention. [Figure 8] FIG. 1 is a front view showing a stabilizer structure using a torsion bar with a double rod structure. [Figure 9] 1 is a front view showing a vehicle suspension structure in which a torsion bar according to the present invention is used. [Figure 10] 1 is a perspective view showing a fixing structure of a vehicle-mounted table using a torsion bar according to the present invention; [Figure 11] FIG. 2 is a side view showing the mounting state of a vehicle-mounted table using the torsion bar of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an axial cross-sectional view of the torsion bar of the present invention. In the torsion bar 10, the reference numeral 11 denotes an inner rod made of a metal round bar or round pipe, the outer periphery of which is covered with a gap by an outer rod 12 made of a metal round pipe, and the axial center of the inner rod 11 and the outer rod 12 is connected by a connecting part 14. The reference numeral 8 denotes a center line showing the axial center of the torsion bar. In forming the torsion bar of this shape, for example, two torsion bars with a Y-shaped cross section, which are shaped like an inner rod folded back outward, are prepared, and the vertical walls, which are the connecting parts connecting the inner rod 11 and the outer rod 12, are bonded together, so that the torsion bar can be formed relatively inexpensively. The inner rod 11 may be made of a round bar depending on the bending strength and the biasing torque of the entire torsion bar 10. In this case, the area of ​​the vertical wall is increased, and the adhesive strength is increased. Furthermore, as shown in FIG. 1(c), the inner rod 11 and the outer rod 12 are divided into two in the axial direction, and the left and right rods 11, 11, 12, 12 are connected via a joint using a spline joint or the like, so that the joint becomes the connecting part 14 and a torsion bar of this shape can be constructed.

[0014] In Fig. 1, reference numerals 15 and 16 denote restricting members located at the axial end of the torsion bar, which are provided to fill the space between the inner rod 11 and the outer rod 12, and which restrict relative movement in the radial direction while allowing relative rotation (twisting) in the axial direction. In this embodiment, the restricting members 15 and 16 are formed integrally with the outer rod 12 and are provided to be loosely fitted into the inner rod 11, but they may be formed integrally with the inner rod 11 as long as they are provided to allow relative rotation between the inner rod 11 and the outer rod 12. Moreover, the restricting members 15 and 16 only need to restrict positional deviation toward the center of the shaft, and may have a bearing structure using ball bearings or the like as shown in Fig. 1(b). Furthermore, when supporting the outer rod 12 so that it can rotate freely in order to fix this torsion bar, by matching the phase between the support portion of the outer rod 12 and the axial position of the regulating members 15, 16, the torsion bar is firmly attached and deformation of the torsion bar itself can be suppressed.

[0015] As shown in Figure 7, by attaching arms 71, 72 to both ends of the inner rod 11 and arms 72, 73 to both ends of the outer rod 12 by an attachment method that involves processing such as gluing, drilling holes, or cutting grooves, it is possible to form a biased pivot structure that has an elastic force for applying or receiving a load to two spaced apart points and an elastic force for resisting the phase difference between the two spaced apart points.

[0016] The torsion bar biasing pivot structure of the present invention configured as described above is a technology that is widely used.

[0017] For example, as shown in Fig. 2, in order to create a hinge 3 that can be biased and pivoted using a common structure of hinge 2, which is the most versatile pivot means for pivotally connecting two metal plates by passing a rod 20 through the bearings of the two bent metal plates, it is common to process the rod 30 so that it is surrounded by the inside diameter of a torsion coil spring 31, as shown in Fig. 3. In this case, rod 30 may be the same as rod 20. Products equivalent to hinge 3 are available under names such as spring hinges.

[0018] However, the hinge technology shown in FIG. 3 does not make high efficiency of material usage, as the axle 30 provides pivoting and the torsion coil spring 31 provides biasing force. While this is not a problem for light loads, making the torsion coil spring out of thicker material to accommodate increased loads can result in the product becoming too bulky. As such, it is thought that there is potential demand for a means to omit coil spring 31, and a means that is structurally stable, lightweight, and cost-effective is desired.

[0019] Therefore, if the shaft rod 20 is designed to store the rotational energy required for biasing, it is possible to omit the torsion coil spring 31. Detailed means will be described step by step below.

[0020] [Powered by pivot rod] The hinge 4 shown in FIG. 4 has arm rods 41 and 42 attached to both ends of the shaft rod 40, and is biased by the torsional biasing force of the shaft rod 40. In this case, the attachment distance between the arm rods 41 and 42 is the effective spring length 46 of the torsion bar spring. However, as a limitation of the hinge 4, an effective spring length 46 of about 500 mm or more is required for an allowable torsion angle of 90°. If the effective spring length 46 is half, 250 mm, the allowable torsion angle is also half, about 45°. Considering that the swing angle of a typical hinge using a torsion coil spring is about 270°, the use of an allowable torsion angle of 45° or less is extremely limited. Although it depends on the type of material and heat treatment, designs that generally exceed this limit may cause the performance of the torsion bar spring to deteriorate in a short period of time, resulting in malfunction. In addition, the two arms that extract the biasing torque are attached at both ends of the shaft rod 40, and the torque is applied via the arms, so the hinge base metal fittings are required to have a certain strength. Therefore, the design thickness of the hinge base increases. Thus, in the biased hinge 4 shown in Figure 4, the torsion coil spring can be omitted in a simple manner, but in return, these problems arise.

[0021] [Method of balancing using double rods] In Fig. 5, the shaft rod and arm rod are of a double rod structure to address the problems of the biased hinge 4 of Fig. 4. In this structure, an inner shaft rod 55, arm rod 51, and arm rod 52 equivalent to the shaft rod 40, arm rod 41, and arm rod 42 shown in Fig. 4 are assembled as an inner rod assembly, and an outer shaft rod 56, arm rod 53, and arm rod 54 are assembled as an outer rod assembly, and the two sets of inner and outer rod sets are pivoted by bearings 57 and 58 at both ends of the outer shaft rod 56 and rotate freely with respect to each other. In the form shown in this figure, as long as the load is evenly applied to the four arm rods 51 to 54, the balance of the biasing forces applied to each arm rod 51 to 54 will not be lost due to problems with the structure itself.

[0022] In this way, by adopting the double rod structure shown in Figure 5, a biasing pivot can be realized with a structure that suppresses the thickness. However, there is a concern that the double rod shown in Figure 5 may deteriorate durability or yield. As already explained, the distance between the bearings at both ends of the double rod is about 250 to 500 mm. The problem of the inner rod and the outer rod contacting each other can be avoided by making the distance between the outer diameter of the inner rod and the inner diameter of the outer rod, that is, the clearance, 1.0 mm or more, but it is desirable to minimize the clearance. The reason is that the expansion of the clearance increases the inner diameter of the outer rod, and as a result, the thickness of the outer rod becomes thinner. The torque per torsion angle of the torsion bar is proportional to the fourth power of the diameter, as shown in Figure 7. This is where the difficulty lies, and the design of the double rod torsion bar must be done accurately. It goes without saying that the thickness of the outer rod will become thinner if the inner diameter of the outer rod is expanded and the outer diameter of the outer rod is not changed. However, making the wall thickness thinner will result in insufficient strength, which will cause other problems. If the inner and outer rods come into contact, this will of course also cause problems. Although it is not impossible to design a 0.5mm outer rod wall thickness and 0.5mm clearance for a torsion bar length of 250 to 500 mm, there is a certain degree of risk of failure.

[0023] [Application example 1] A biased hinge 7 employing a torsion bar of the present invention is shown in Figure 7. It is clear that the effects of the invention in biased hinge 7 have resolved, firstly, the issue around the axis addressed in the general biased hinge 3 in Figure 3, and secondly, the issue of balance addressed in biased hinge 4 using a torsion bar in Figure 4. As for the issues of eccentricity and clearance of the double axis addressed in the biased hinge using a torsion bar with a double rod structure in Figure 5, biased hinge 7 can avoid the effects of eccentricity with minimal clearance by integrating the center of the double rod structure 10.

[0024] [Stabilizer effect] As mentioned above, the present invention is a technology devised to aim for a compact and powerful biasing pivot structure, but the effect of the present invention is not limited to that. When the double-rod pivot is applied to a vehicle suspension system, it is possible to suppress posture change during cornering with a compact structure. The details are explained below.

[0025] Generally, when a vehicle turns, the suspension system is subjected to centrifugal force, causing a lateral change in posture, known as rolling. A part used to suppress rolling and improve turning performance is called a stabilizer or anti-roll bar. For the sake of explanation, Fig. 8 shows a structure without a central connector, as in Fig. 5 above. In Fig. 8, arm rod 81, pivot rod 85, and arm rod 84 form an inner rod assembly, and arm rod 82, pivot rod 86, and arm rod 83 form an outer rod assembly. In this case, when both ends of the pivot of the outer rod assembly and the two arm rods 82, 83 are fixed to the vehicle frame side via simple cushioning members such as rubber bushes, the inner rod assembly is pivotally attached by two bearings 15, 16 attached to both ends of the pivot of the outer rod assembly. Furthermore, if two axles are attached to the arm rods 81 and 84 of the inner axle rod assembly, the stabilizer will be connected to the axles of the independent vehicle suspension. In other words, the inner rod assembly shown above has the effect of a roughly U-shaped stabilizer as it is. If the inner rod and outer rod are integrated here, a biasing force will be applied, and the basic structure of the vehicle suspension will be completed.

[0026] [Application example 2] As a second application example of the torsion bar of the present invention, a plan view of a rear axle 8 of a vehicle suspension is shown in Figure 9. The axle 8 is similar to the torsion beam type, which is currently the most commonly used type among the numerous conventional types. The decisive difference between the axle 8 and the conventional torsion beam type is that the coil spring is omitted. In the conventional torsion beam type, the coil spring is used to bias the trailing arm near the axle, but in the method of the vehicle suspension 8 of this application example, the inner rod mainly replaces the beam to provide a stabilizer effect, and biases the axle by the torsion angle of the dual structure of the inner and outer rods. As a result, firstly, the device can be simplified, and the unsprung weight, which is an indicator of the performance of the vehicle suspension, is reduced. In addition, when the wheels attached to the vehicle suspension 8 pick up unevenness in the road surface and vibrate during driving, the weight of the pivot, which is the center of rotation, can be almost ignored, so the effective unsprung weight is almost only the weight of the two wheels. In addition, although there are arm rods 81, 84 attached to the inner rod, it can be said that the overall structure is almost ideally light. Secondly, the spring strength of the outer rod and the inner rod becomes the biasing force that supports the weight of the vehicle body, and the spring strength of the inner rod becomes the stabilizer effect, so the design value is simple and easy to adjust. Thirdly, the system of the vehicle suspension 8 has good left and right balance because the biasing torque is concentrated at only one point in the center. Fourthly, it has a simple structure in which a straight shaft rod is supported by bearings 15, 16 at both ends, and depending on the bearings, precision and strength can be reliably ensured. Fifthly, not using a coil spring, which has complex elements such as vibration and friction, simplifies everything. In conclusion, this technology can be widely applied to vehicles such as passenger cars, and it will also make it possible to equip three-wheeled bicycles, which have a width of only about 500 mm, with suspension systems with stabilizers.

[0027] [Application example 3] FIG. 10 shows a view of the biasing pivot attachment attached to the leg of the vehicle-mounted table as the third embodiment. The arm rods 101, 103 attached to the inner rod 11 and the arm rods 102, 104 attached to the outer rod provide support between the backrest of the front seat 124 and the floor. Conventional rear seat tables for sedan-type vehicles are mainly small ones attached to the backrest of the front seat, which are somewhat inconvenient for eating or working on a laptop computer, but this is thought to be a specification that takes safety into consideration, assuming that the table will be used while driving. In contrast, the vehicle-mounted table of the third embodiment is intended to be used mainly for camping or when one person is riding, and is intended to be used when the vehicle is parked and stopped, and is installed in the manner shown in FIG. 11, and has sufficient size, strength, load capacity, etc. for such purposes.

[0028] As shown in the reference side view (FIG. 11) of the use example 3, four components are combined and used to install the in-vehicle table. The four components are a front seat 124, left and right seat rails 121, 121, and an in-vehicle table 123. Two legs, left and right, of the in-vehicle table 123 are rotatably supported on the left and right seat rails 121, 121, the arm rods 101, 103 on the inner rod 11 side are connected to the legs of the table, and the arm rods 102, 104 on the outer rod 12 side are abutted against the floor surface. The method of rotatably supporting the in-vehicle table 123 on the vehicle body side is not limited to this embodiment, and in some cases it may be possible to support it by using a torsion bar as a rotation axis, in which case it can be supported relatively firmly and stably by supporting the outer rod 12 near the restricting parts 15, 16. Also, if it is supported at both ends of the inner rod 11 protruding from the outer rod 12, it is possible to suppress an increase in the lateral width. The figure also shows three arrows representing stress 131, stress 132, and stress 133. These three stresses are the only ones that the in-vehicle table 123 directly exerts on other components. These three stresses are mainly determined by the weight of the in-vehicle table, the load on the top plate, and the strength of the biasing force of the torsion bar. When the load on the top plate increases, the clockwise moment at the fulcrum 127 on the seat rail in FIG. 11 becomes stronger, and when stress 133 becomes 0, the table becomes unstable and starts to tip over toward the user. In terms of design, the biasing force of the torsion bar is adjusted so that stress 133 becomes 0 immediately after the load on the top plate reaches the maximum load capacity of the product. This allows the user to become aware of the limitations of the product. In addition, since several mats are usually laid irregularly under the feet of a passenger sitting in the rear seat of a vehicle, and the floor is not flat, a stroke difference occurs between the arm rod 102 and the arm rod 104 attached to the outer rod. In the torsion bar of the present invention, the only torque transmission path from the outer rod to the inner rod is the joint in the center, so the effect of the stroke difference is mitigated there, and the difference in the left and right biasing forces caused by the left and right stroke difference can be reduced, enabling stable support of the vehicle-mounted table 123. On the other hand, when a heavy load is placed on either the left or right side of the table top, this is reflected in the balance of the stress applied to the arm rod 101 and the arm rod 103 attached to the inner rod, but unstable behavior is suppressed by the stabilizer effect of the spring of the inner rod, just as when centrifugal force is applied to the suspension. [Explanation of symbols]

[0029] 8. Center line showing the common axis center of the torsion bar of the present invention 10 Torsion bar 11 Inner rod 12 Outer rod 14 Connecting part 15,16 Regulatory members

Claims

1. A torsion bar comprising an inner rod having a circumferential torsional elastic force, an outer rod containing the inner rod and having a circumferential torsional elastic force, a connecting portion that fixes and connects the inner rod and the outer rod at the axial center, and connecting portions at both axial ends of the inner rod and the outer rod to an object to which an elastic force is applied.

2. 2. The torsion bar according to claim 1, characterized in that a restricting portion is provided between the inner rod and the outer rod and on the axial end side thereof, which restricts relative radial movement between the inner rod and the outer rod while allowing relative rotation in the circumferential direction of the axis.

3. 3. The torsion bar according to claim 2, wherein the restricting portion is provided immediately adjacent to a pivotal support portion that positions and supports the outer rod.

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