JPH0581546U - Front fork for motorcycle - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] When using a spring composed of multiple spring bodies in a motorcycle front fork, the setting of the composite spring constant can be diversified and the fall of the spring can be prevented easily. It is possible. In a motorcycle front fork 10 in which an inner cylinder and an outer cylinder are slidably fitted and a buffer coil spring 34 is interposed between the inner cylinder and the outer cylinder, a plurality of springs 34 are provided. 34A and 34B are connected in series to form each spring body 34.
The wires A and 34B are screwed and joined to each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a front fork for a motorcycle.

[0002]

[Prior Art]

 Conventionally, as a front fork for a motorcycle, there is one disclosed in Japanese Patent Laid-Open No. 57-167883. This front fork is formed by slidably fitting an inner cylinder and an outer cylinder, and a buffer coil spring is interposed between the inner cylinder and the outer cylinder. It is made up of connections. At this time, the spring bodies are connected in series with each other with the connecting pieces sandwiched therebetween and their seating surfaces seated on the connecting planes of the connecting pieces.

[0003]

[Problems to be solved by the device]

However, the conventional technique has the following problems. The spring constant k of each spring body is k = Gd ⁴ / 8D ³ n (n is the number of turns, d is the wire diameter, D is the coil diameter, and G is the lateral elastic coefficient of the material) and is a function of the number of turns n. The combined spring constant K of the entire spring is 1 / K = (1 / ka) + (1 / kb) (ka and kb are spring constants of each spring body). Therefore, as long as the total length of the spring is constant and the material, pitch, wire diameter, and coil diameter of each spring body are the same, the setting factor of the composite spring constant changes the number of turns (length) of each spring body. Therefore, there is a limit to the diversification of the setting of the composite spring constant.

The spring bodies are connected in series with one another with their bearing surfaces seated on the connecting planes of the connecting pieces. Therefore, not only is it necessary to machine the seat surface of each spring body at right angles, but depending on the accuracy of the seat surface at right angles, the axis of each spring body is inclined with respect to the connection plane of the connecting piece, and There is a possibility that the connection portion of each spring body may be broken and the spring may fall down, resulting in malfunction. In the front fork, since the spring has a long total length and the wire diameter is small, the above-mentioned tilt is likely to occur.

The present invention makes it possible to diversify the setting of the composite spring constant when using a spring consisting of a plurality of spring bodies in a motorcycle front fork, and yet to prevent the spring from falling over easily. To aim.

[0006]

[Means for Solving the Problems]

 The present invention relates to a front fork for a motorcycle, in which an inner cylinder and an outer cylinder are slidably fitted, and a buffer coil spring is interposed between the inner cylinder and the outer cylinder. The spring body is constructed by connecting the bodies in series, and the respective spring bodies are formed by connecting their strands by screwing them together.

[0007]

[Action]

 According to the present invention, there are the following effects. Assuming that the buffer spring is composed of, for example, a combination of a first spring body and a second spring body, the combined spring constant K of the entire spring is

[Equation 1] Is. Where ka ₁ is the spring constant of the non-screw joint of the first spring body, ka ₂ is the spring constant of the screw joint of the _first spring body, and kb ₁ is the non-screw joint of the second spring body. The spring constant, kb _2, is the spring constant of the threaded joint of the second spring body. Therefore, when the total length of the spring is constant and the material, pitch, wire diameter, and coil diameter of each spring body are the same, the setting factor of the composite spring constant is (a) the number of turns (length) (B) The number of turns (length) of the threaded joint of each spring body is changed, and the setting of the composite spring constant can be diversified.

The spring bodies can be made uniaxial by screwing and coupling them. Therefore, it is not necessary to machine the seating surfaces of the connecting ends of the spring bodies at right angles to each other, and the entire spring can be connected in series in a straight shape without breaking. As a result, it is possible to easily prevent the spring from collapsing, and thus the malfunction.

[0009]

【Example】

 FIG. 1 is a sectional view showing a front fork for a motorcycle according to an embodiment of the present invention, FIG. 2 is a sectional view showing a main part of FIG. 1, FIG. 3 is a schematic diagram showing a piston of a damper cylinder, and FIG. 5 is a schematic diagram showing a rotating structure, FIG. 5 is a schematic diagram showing a fitting structure between an adjusting rod and a spring receiving and driving member, FIG. 6 is a schematic diagram showing a temperature compensating structure, and FIG. 7 is a schematic diagram showing a buffer spring.

The front fork 10 for a motorcycle is an inverted type in which the inner cylinder 11 is arranged on the axle side, the inner cylinder 11 and the outer cylinder 12 are slidably fitted together, and the damper cylinder is placed inside the inner cylinder 11. 13, a piston 15 having a damping force generator 14 is slidably fitted inside the damper cylinder 13, and oil is provided inside the outer cylinder 12 and the inner cylinder 11 outside the damper cylinder 13. The reaction force chamber 16 composed of the chamber 16A and the gas chamber 16B is configured.

A cap 17 is screwed to the lower end of the outer cylinder 12 via seals 17A and 17B. The cap 17 holds a seal 18 and a bearing 19 in contact with the outer peripheral surface of the inner cylinder 11. .. Further, a fork bolt 22 is screwed to the upper end portion of the outer cylinder 12 via a seal 21, and a bearing 23 that is in contact with the outer peripheral surface of the inner cylinder 11 is held at the upper end side intermediate portion of the outer cylinder 12. .. The axle holder 24 is screwed to the lower end of the inner cylinder 11. 24A is an axle mounting hole.

A cylinder mounting collar 26 is fixed to a lower end portion of the inner cylinder 11 by a mounting bolt 25, and a lower end outer peripheral portion of a damper cylinder 13 is fixed to an inner upper end portion of the collar 26 by screwing. 27 is a lock nut.

A spring adjustment dial 28 is fitted to the inner peripheral portion of the fork bolt 22 provided at the upper end of the outer cylinder 12 via a seal 29, and the outer cylinder 12 of the spring adjustment dial 28 is fitted. A dial locking member 31 is screwed to the small outer diameter portion of the lower end located inside, and the pivot adjusting dial 28 is rotatably connected. Then, a spring receiver 32 is further screwed to the small outer diameter portion of the lower end located in the outer cylinder 12 of the spring adjusting dial 28. The spring receiver 32 and a spring receiver on the upper end side of the damper cylinder 13 which will be described later. A buffer spring 34 is interposed between the buffer spring 33 and 33. The spring receiver 32 is provided with a protrusion 36 that engages with a detent groove 35 formed in the axial direction of the inner surface of the fork bolt 22. As a result, when the spring adjusting dial 28 is rotated, the spring receiver 32 screwed to the small outer diameter at the lower end of the dial 28 is moved in the axial direction, and the initial set length of the spring 34 can be adjusted. And

In the front fork 10, the gas in the gas chamber 16B and the spring 34 generate a repulsive force when the inner cylinder 11 and the outer cylinder 12 contract, and the vehicle weight of an occupant or the like or the impact force from the wheel side. To support the.

An oil hole 37 penetrating in and out is provided above the upper end of the damper cylinder 13 of the inner cylinder 11, and a part of the oil in the oil chamber 16 A is divided between the inner cylinder 11 and the outer cylinder 12. The bearings 19 and 23 described above can be lubricated by introducing them between them.

However, in the damper cylinder 13, the hollow piston rod 41 that fixes the piston 15 is extended to the outside of the cylinder 13 through the seals 42 and 43, and the lower end of the piston rod 41 is the cylinder. The free end extends into the mounting collar 26, and the upper end of the piston rod 41 is fixed to the outer cylinder 12 side. Here, the upper end portion of the piston rod 41 is provided with a seal 46 on a rod mounting member 45 that is screwed and fixed to a lower end inner diameter portion located inside the outer cylinder 12 of the spring adjusting dial 28 with a seal 44. It is fixed by screwing. 47 is a lock nut. As a result, when the inner cylinder 11 and the outer cylinder 12 expand and contract, the damper cylinder 13 remains stationary on the inner cylinder 11 side, the piston rod 41 moves together with the outer cylinder 12, and the piston 15 moves inside the cylinder 13. Becomes

A rod guide 49 is fixed to the inner diameter of the lower end of the damper cylinder 13 via a seal 48, and the rod guide 49 holds the above-mentioned seal 42 in contact with the outer peripheral surface of the piston rod 41.

A rod guide 53 is fixed to the inner diameter of the upper end of the damper cylinder 13 via a seal 52, and the rod guide 53 holds the above-mentioned seal 43 in contact with the outer peripheral surface of the piston rod 41. A partition wall member 55 is fixed to the outer diameter portion of the upper end of the damper cylinder 13 via a seal 54, and the partition wall member 55 holds a seal 56 in contact with the inner peripheral surface of the inner cylinder 11. As a result, in the front fork 10, the upper end of the damper cylinder 13 and the inner cylinder 11 and the outer cylinder 12 are tightly sealed to each other, and above the damper cylinder 13, the oil chamber 16A and the gas chamber 16B are formed. The force chamber 16 is configured.

The lower end of the collar 57 is mounted on the outer periphery of the upper end of the partition wall member 55, and the spring receiver 33 of the spring 34 is supported on the upper end of the color 57.

However, the damping force generator 14 of the front fork 10 is configured as follows around the piston rod 41. The piston rod 41 includes a lower hollow rod 41A, an oil lock piece 41B screwed to the upper outer diameter portion of the lower hollow rod 41A, and a female screw screwed to the upper inner diameter portion of the oil lock piece 41B. The member 41C is composed of four members, that is, an upper hollow rod 41D that is screwed to the inner diameter of the upper end of the female screw member 41C. Reference numeral 58 is a lock nut.

The damping force generator 14 has oil passages 61, 62, 63 which are provided inside the piston rod 41 in which the piston 15 is fixed and which connect the upper and lower oil chambers 59 A, 59 B of the piston 15. Prepare The oil passage 61 is formed in the female screw member 41C, the oil passage 62 is formed by the inner diameter portion of the female screw member 41C, and the oil passage 63 is formed in the oil lock piece 41B. A check valve 63A is provided at the outlet of the oil passage 63. As a result, the oil passages 61 to 63 form a pull-side passage.

As shown in FIG. 3, the damping force generator 14 is provided on the outer periphery of the piston rod 41 to open and close the pull-side flow passage 64 and the push-side flow passage 65 of the piston 15, respectively. A side disc valve 66 and a push side disc valve 67 are provided. The pull-side disc valve 66 is supported by a spacer 68 back-supported by the oil lock piece 41B, and the push-side disc valve 67 is supported by a spacer 69 back-supported by the female screw member 41C. The push-side disc valve 67 is back-supported via a pressing member 73 by a valve spring 72 supported by a valve spring receiver 71 mounted on the outer peripheral portion of the female screw member 41C, and the mounting length of the valve spring 72 changes. The opening pressure can be adjusted by changing the spring force based on.

At this time, an adjusting rod 74 is provided inside the upper hollow rod 41D constituting the piston rod 41 so as to be movable and rotatable in the axial direction. By the axial movement of the tip needle valve 74A, the opening area of the piston rod internal oil passage 62 as the above-mentioned pull-side flow passage is adjusted, and thus the pull-side damping force can be adjusted. Further, (b) by adjusting the attachment length of the valve spring 72 by adjusting the opening of the push-side disc valve 67 by moving the valve spring receiver 71 by the rotation of the adjusting rod 74, it is possible to reduce the push-side damping force. Adjustable.

The moving structure of the valve spring receiver 71 in the above (b) is as follows. That is, the pin 75 integrated with the valve spring receiver 71 projects into the slit 76 provided in the female screw member 41C. On the other hand, as shown in FIG. 5, a male screw member 77 that is movable only in the axial direction is fitted to the slit end surface portion 74B of the adjusting rod 74, and the male screw member 77 is screwed to the female screw member 41C. As a result, when the adjusting rod 74 rotates, the male screw member 77, which rotates integrally with the adjusting rod 74, is screwed with respect to the female screw member 41C and advances in the axial direction, and the end face of the male screw member 77 is pin 75 of the valve spring catch 71. And then the valve spring receiver 71 is moved, and as a result, the mounting length of the valve spring 72 can be adjusted.

Further, the rotation of the adjusting rod 74 for adjusting the pushing-side damping force in the above (b) is performed by the following structure. That is, the fixing ring 78 is screwed to the inner diameter portion on the outer end side of the spring adjusting dial 28 described above, and the pressing ring 81 and the locking member 82 are integrated by the bolts 83. By sandwiching 78 from both sides, the push side dial 81 and the locking member 82 can be rotated only. As shown in FIG. 4, a slit 84 is provided at the tip of the locking member 82, and a pin 85 is provided at the proximal end of the adjusting rod 74 so that the slit 84 and the pin 85 are always engaged. As a result, when the push-side dial 81 is rotated, the adjusting rod 74 is rotated through the engagement of the slit 84 and the pin 85.

Further, the axial movement of the adjusting rod 74 for adjusting the pulling side damping force in the above (a) is performed by the following structure. That is, the screw shaft 86 is screwed to the locking member 82 integrated with the push-side dial 81, and the pull-side dial 87 is fixed to the outward protruding end of the screw shaft 86 by the set screw 88. On the other hand, the retaining ring 91 is locked around the outer end of the adjusting rod 74 that penetrates the rod mounting member 45, and the rod return spring 92 is provided between the end surface of the rod mounting member 45 and the retaining ring 91. The outer end surface of the adjusting rod 74 is constantly pressed against the inner end surface of the screw shaft 86 by the elastic force of the spring 92. As a result, when the pull-side dial 87 is rotated, the screw shaft 86 is screwed and moved by the locking member 82, which in turn moves the adjustment rod 74 in the axial direction. A detent ball 93 is built in around the screw shaft 86 of the locking member 82, and the detent ball 93 is provided in any of a number of concave grooves provided in the circumferential direction of the outer peripheral portion of the screw shaft 86. Sequential engagement is performed, and the rotary operation position of the pull side dial 87 can be varied in multiple stages.

Further, in the front fork 10, a compensation chamber 94 having a temperature compensation function is provided inside the piston rod 41. That is, as shown in FIG. 6, the orifice body 96 is fitted to the inner diameter portion of the lower hollow rod 41A communicating with the oil passages 61 to 63 through the seal 95, as shown in FIG. Has a slit 97 engraved in the diametrical direction, and a check valve 99, which is back-supported by a spring 98, is pressed against the end face of the slit. 96A is an orifice. The inner diameter of the lower hollow rod 41A from the orifice body 96 is defined as an oil chamber 100, and a plunger 101 is axially movable in the innermost portion of the compensation chamber 94. At this time, a cap 102 is sealed on the inner diameter of the lower end of the lower hollow rod 41A, and the space between the cap 102 and the plunger 101 serves as the above-mentioned compensation chamber 94, and the air and the compression spring 103 are placed in the compensation chamber 94. Built-in. As a result, the oil that expands due to the increase in the oil temperature in the damper cylinder 13 escapes from the oil passages 61 to 63 into the oil chamber 100 through the slit 97 of the orifice body 96 and the orifice 96A, and compresses the compensation chamber 94. Be absorbed. After that, when the oil temperature in the damper cylinder 13 decreases, the compensation chamber 94 expands and the above-mentioned oil that has escaped into the oil chamber 100 is returned to the damper cylinder 13 side.

In the front fork 10, the oil lock housing 111 is fixed to the lowermost end of the lower chamber 59 B of the damper cylinder 13, and when the inner cylinder 11 and the outer cylinder 12 are contracted again, the piston rod is closed. By inserting the tip of the oil lock piece 41B of 41 into the oil lock housing 111, the hydraulic pressure between the two is increased, and cushioning is performed at the pushing stroke end.

Further, in the front fork 10, the rebound spring 112 is arranged at the uppermost end of the upper chamber 59 A of the damper cylinder 13, and when the inner cylinder 11 and the outer cylinder 12 are re-extended, The upper end surface of the female screw member 41C of 41 collides with the rebound spring 112 to compress the spring 112, and cushioning is performed at the pull-side stroke end.

Here, in the front fork 10, the above-mentioned buffer spring 34 is configured by connecting two first and second spring bodies 34A and 34B in series, and each spring body 34A and 34B is The elemental wires are partially screwed and connected to each other.

At this time, the total synthetic spring constant K of the spring 34 is

[Equation 2] Is. Where ka ₁ is the spring constant of the non-screw joint of the first spring body, ka ₂ is the spring constant of the screw joint of the _first spring body, and kb ₁ is the non-screw joint of the second spring body. The spring constant, kb _2, is the spring constant of the threaded joint of the second spring body. If the spring bodies 34A and 34B have the same material, pitch, wire diameter, and coil diameter, ka ₂ = kb ₂ , and if they have the same length, ka ₁ = kb ₁ .

The operation of the front fork 10 will be described below. (1) When the inner cylinder 11 and the outer cylinder 12 of the front fork 10 are compressed, the lower chamber 59B of the damper cylinder 13 contracts, and the oil pushes up the push-side disc valve 67 from the push-side flow passage 65 of the piston 15 and opens it. It moves to the chamber 59A and generates a push-side damping force. At this time, the gas in the gas chamber 16B and the spring 34 generate a repulsive force to elastically support the vehicle-mounted weight of an occupant or the like, or the impact force from the wheel side.

(2) When the inner cylinder 11 and the outer cylinder 12 of the front fork 10 extend, the upper chamber 59A contracts, and a part of the oil flows from the pull-side passage 64 of the piston 15 to the pull-side disc valve. 66 is pushed open to move to the lower chamber 59B, and the other part is passed through the oil passage 61 in the piston rod 41, the oil passages 62 and 63 narrowed to the needle valve 74A, and the check valve 63A to the lower chamber. It moves to 59B and a pull-side damping force is generated.

Next, the operation of this embodiment will be described. In the buffer spring 34, when the total length of the spring 34 is constant and the material, pitch, wire diameter, and coil diameter of each spring body 34A, 34B are the same, the setting factor of the composite spring constant K is (a) To change the number of turns (length) of each spring body 34A, 34B as a single item, (b) To change the number of turns (length) of the threaded joints ka ₂ , kb ₂ of each spring body 34A, 34B. Therefore, the setting of the composite spring constant K can be diversified.

The spring bodies 34A, 34B can be made uniaxial by screwing and coupling. Therefore, it is not necessary to process the seating surfaces of the connection ends of the spring bodies 34A and 34B at right angles to the axis, and the entire spring 34 can be connected in series in a straight shape without breaking. As a result, it is possible to easily prevent the spring 34 from collapsing and, consequently, malfunctioning.

In the implementation of the present invention, the outer cylinder is an upright front fork arranged on the axle side, the damper cylinder is fixed to the lower outer cylinder, and the piston rod of the damper cylinder is the upper side. It may be fixed to the inner cylinder.

[0037]

【The invention's effect】

 As described above, according to the present invention, when a spring composed of a plurality of spring bodies is used in a motorcycle front fork, it is possible to diversify the setting of the composite spring constant and still prevent the spring from falling over easily. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view showing a front fork for a motorcycle according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of FIG.

FIG. 3 is a schematic diagram showing a piston of a damper cylinder.

FIG. 4 is a schematic view showing a rotating structure of an adjusting rod.

FIG. 5 is a schematic view showing a fitting structure of an adjusting rod and a spring receiving drive member.

FIG. 6 is a schematic diagram showing a temperature compensation structure.

FIG. 7 is a schematic view showing a buffer spring.

[Explanation of symbols]

 10 Front Fork 11 Inner Cylinder 12 Outer Cylinder 34 Spring 34A, 34B Spring Body

Claims (1)

[Scope of utility model registration request] 1. A front fork for a motorcycle, wherein an inner cylinder and an outer cylinder are slidably fitted to each other, and a buffer coil spring is interposed between the inner cylinder and the outer cylinder. A front fork for a motorcycle, which is configured by connecting bodies in series, and each spring body is formed by threading and connecting respective strands of the spring body to each other.