JP7507526B1 - Bead Separator - Google Patents

Abstract

[Problem] To provide a bead breaking device. [Solution] The bead breaking device 1 includes a main body 2, an arm 5, a blade 3 attached to the free end of the arm 5, a compressed air pressure source 6, a double-acting pneumatic cylinder CY1 having a first port 8a and a second port 8b, a flow path configuration unit 10 configured to be switchable between a first flow path that guides compressed air to the first port 8a and releases it to the atmosphere from the second port 8b, a second flow path that guides compressed air to the second port 8b and releases it to the atmosphere from the first port 8a, and a third flow path that guides compressed air to the second port 8b and reduces the pressure of the compressed air before directing it to the first port 8a, a pressure reducing valve V5 interposed in the flow path connecting the compressed air pressure source 6 and the first port 8a and reducing the pressure of the compressed air guided to the flow path, and an operation unit 9 that can select between the first flow path, the second flow path, and the third flow path. [Selected Figure] Figure 1

Description

This disclosure relates to a bead separation device that is installed in a tire changing machine or the like.

Conventionally, high-rigidity tires, also known as low-profile tires reinforced with wire or carbon fiber, are difficult to remove from or attach to wheels by hand, so a tire changing device, also known as a tire changer or tire changing machine, has been used. This tire changing device is equipped with a bead separating device for separating the bead portion of the high-rigidity tire from the rib portion of the wheel. Such a bead separating device is disclosed, for example, in Patent Document 1.

JP 2011-31645 A

In the bead separating device of Patent Document 1, when the bead portion of the tire is separated from the rim portion of the wheel, the bead portion is separated while being pressed with a high pressing force by the blade driven by the double-acting pneumatic cylinder. Therefore, when the bead portion comes off the rim portion, the reaction force from the bead portion that the blade receives drops suddenly, and the blade comes into contact with the rim portion due to the action of the pressure of the double-acting pneumatic cylinder, which may damage the rim portion.

The object of the present invention is to provide a bead separation device that prevents the blade from coming into contact with the rim and being damaged due to a sudden drop in the reaction force of the blade when the bead is separated from the rim.

The present invention relates to a tire-equipped wheel-supporting device, and a main body having a rotary table that can hold the tire-equipped wheel and rotate around a rotation axis;
an arm having a free end and a base end connected to the main body portion so as to be rotatable about an axis parallel to the rotation axis;
a blade provided on the free end of the arm for pressing a bead portion of a tire of a tire-mounted wheel arranged in an upright state on the side of the main body;
A compressed air pressure source that generates compressed air;
a double-acting pneumatic cylinder including a piston rod that moves in a first direction or a second direction opposite to the first direction and is connected to the arm, a first port to which the compressed air is supplied when the piston rod is moved in the first direction, and a second port to which the compressed air is supplied when the piston rod is moved in the second direction;
a flow path configuration unit that is switchable between a first flow path that guides the compressed air to the first port and opens the compressed air from the second port to the atmosphere, a second flow path that guides the compressed air to the second port and opens the compressed air from the first port to the atmosphere, and a third flow path that guides the compressed air to the second port and reduces the pressure of the compressed air before directing it to the first port;
a pressure reducing valve that is interposed in a flow path connecting the compressed air pressure source and the first port and reduces the pressure of the compressed air introduced into the flow path;
and an operation unit capable of selecting any one of the first flow path, the second flow path, and the third flow path.

The present invention is also characterized in that it includes a first connecting part that connects the blade to the free end of the arm so that the blade can be angularly displaced about an axis parallel to the rotation axis.

The present invention is also characterized in that it includes a second connecting part that connects the blade to the first connecting part so that the blade can be angularly displaced about a horizontal axis.

According to the present invention, the flow path selection unit selects one of the first flow path, the second flow path, and the third flow path by the operation unit. When the first flow path is selected, compressed air is supplied to the first port and the compressed air is released to the atmosphere from the second port, so that the piston rod of the double-acting pneumatic cylinder can be moved in the first direction to move the blade away from the main body and form a tire loading space between the main body and the blade. When the second flow path is selected by the operation unit, compressed air is supplied to the second port and the compressed air is released to the atmosphere from the first port, so that the piston rod can be moved in the second direction to press the bead portion with the blade and separate the bead portion from the rim portion. When the operator operates the operation unit to select the third flow path just before the bead portion is separated from the rim portion, compressed air is supplied to the second port and compressed air decompressed by the pressure reducing valve is supplied to the first port. As a result, even if the bead portion separates from the rim portion and the reaction force from the bead portion to the blade suddenly decreases, the movement of the piston rod in the second direction is braked by the pressure of the compressed air decompressed by the pressure reducing valve, and the sudden displacement of the blade in the second direction is suppressed. This reduces the impact of the blade in the second direction and suppresses damage caused by contact of the blade with the wheel.

In addition, according to the present invention, the blade is connected to the free end of the arm by the first connecting portion, so that the position of the blade can be adjusted around an axis parallel to the axis of rotation according to the size of the tire mounted on the wheel, and positioned near the bead portion of the tire and the rim portion of the wheel. This allows the pressing position of the blade to be positioned opposite the bead portion to perform the bead separation operation, and even when the tire sizes are different, the bead separation operation can be performed smoothly, improving workability.

In addition, according to the present invention, the blade and the first connecting part are connected by the second connecting part, so that the position of the blade can be adjusted around the horizontal axis according to the size of the tire to be mounted on the wheel, and the pressing position of the blade can be positioned to face the bead portion. This allows the blade to be positioned appropriately according to the size of the tire and the bead separation work can be performed, making the bead separation work smoother and improving workability.

1 is a simplified plan view showing a bead breaking device 1 according to an embodiment of the present invention; FIG. 2 is a side view of the bead breaking device 1 as viewed from below in FIG. 2 is a cross-sectional view showing a connection structure between a plate 3 and an arm 5 of the bead breaking device 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. 2 is an exploded perspective view of a first connecting portion 11 and a second connecting portion 12. FIG. 2 is a pneumatic circuit diagram showing the configuration of a flow path configuration unit 10. FIG. 4 is a pneumatic circuit diagram for explaining a first flow path of a flow path configuration unit 10. FIG. 4 is a pneumatic circuit diagram for explaining a second flow path of the flow path configuration unit 10. FIG. 4 is a pneumatic circuit diagram for explaining a third flow path of the flow path configuration unit 10. FIG. 13 is a graph showing an air pressure reaction force R1 and a spring reaction force R2 in a shock mitigation effect confirmation test. FIG. 11 is a cross-sectional view showing a single-acting pneumatic cylinder CY2 used for measuring a spring reaction force R2. 1 is a front view showing an example of a tire mounting/removal device 31 equipped with a bead separating device 1. FIG. FIG. 2 is a plan view of the tire mounting/removal device 31.

Figure 1 is a simplified plan view of a bead breaking device 1 according to one embodiment of the present invention, and Figure 2 is a side view of the bead breaking device 1 as viewed from below in Figure 1. In the following description, the tire T is assumed to be a high-rigidity tire such as a run-flat tire or a low-profile tire reinforced with metal wire or carbon fiber.

The bead separating device 1 of this embodiment includes a main body 2, an arm 5, a blade 3, a compressed air pressure source 6, a double-acting pneumatic cylinder CY1, a flow path configuration unit 10, a pressure reducing valve V5 (see FIG. 6A described later), and an operation unit 9. As shown in FIG. 9 and FIG. 10 described later, the main body 2 includes a rotary table 34 that holds a tire-equipped wheel and is rotatable about a rotation axis L31 that extends vertically. The arm 5 has a free end 5a and a base end 5b that is connected to the main body 2 so as to be rotatable about an axis L1 that is parallel to the rotation axis L31.

The blade 3 is provided at the free end 5a of the arm 5, and is a member for pressing the bead portion TB of the tire of the tire-mounted wheel (hereinafter, sometimes referred to as the "tire already mounted on the wheel" or simply the "tire") T that is arranged in an upright state to the side of the main body portion 2. The compressed air pressure source 6 generates compressed air. The compressed air pressure source 6 may be configured to include, for example, an air compressor installed in a factory and piping in the factory to which the compressed air discharged from the air compressor is supplied. The compressed air from the compressed air pressure source 6 is supplied to the first pipe m1. The second pipe m2 (see FIG. 6 described later) branches off and is connected to the first pipe m1. The pressure of the compressed air generated by the compressed air pressure source 6 is set to, for example, 1.0 MPa.

The double-acting pneumatic cylinder CY1 has a piston rod 7, a first port 8a, and a second port 8b. The piston rod 7 moves in a first direction A1 or a second direction A2 opposite to the first direction A1, and is connected to the arm 5. The first port 8a is supplied with compressed air from the compressed air pressure source 6 when the piston rod 7 is moved in the first direction A1. The second port 8b is supplied with compressed air from the compressed air pressure source 6 when the piston rod 7 is moved in the second direction A2. The flow path configuration unit 10 is configured to be switchable between a first flow path (see FIG. 6B) that guides compressed air to the first port 8a and releases it to the atmosphere from the second port 8b, a second flow path (see FIG. 6C) that guides compressed air to the second port 8b and releases it to the atmosphere from the first port 8a, and a third flow path (see FIG. 6D) that guides compressed air to the second port 8b and reduces the pressure of the compressed air before directing it to the first port 8a. The pressure reducing valve V5 is disposed in the flow path connecting the compressed air pressure source 6 and the first port 8a, i.e., the sixth pipe m6 described below, and reduces the pressure of the compressed air introduced into this flow path. The operation unit 9 can select one or more of the first flow path, the second flow path, and the third flow path.

Figure 3 is a cross-sectional view showing the connection structure between the blade 3 and the arm 5 of the bead breaking device 1, and Figure 4 is a cross-sectional view taken along the cutting line IV-IV in Figure 3. Figure 5 is an exploded perspective view of the first connecting part 11 and the second connecting part 12. Note that the side plate 89 of the arm 5 is omitted from Figure 3 for ease of illustration. The bead breaking device 1 includes a first connecting part 11 that connects the blade 3 to the free end part 5a of the arm 5 so as to be angularly displaceable about an axis L2 parallel to the rotation axis L31, and a second connecting part 12 that connects the blade 3 so as to be angularly displaceable about two axes L3 and L4 perpendicular to the axis L2 of the first connecting part 11.

In other embodiments of the present invention, the bead breaking device 1 may be configured to include only one of the first connecting portion 11 and the second connecting portion 12, or may be configured to be connected by a universal joint or the like to allow angular displacement in all directions.

The first connecting portion 11 has a first shaft 14 and a bracket 15 to which both axial ends of the first shaft 14 are fixed, for example, by welding. The first shaft 14 and bracket 15 are made of, for example, structural steel.

The bracket 15 is, for example, rectangular, and has a first hole 15a in which the first shaft 14 is attached, and a second hole 15b parallel to the first hole 15a. The second shaft 80 is removably attached to the second hole 15b. The arm 5 has an upper plate 81, a lower plate 82, and a side plate 89. Two through holes 84a, 84b through which the second shaft 80 can be inserted and removed are formed in the free end 5a side of the upper plate 81 and the lower plate 82. In addition, an insertion hole 88 through which the first shaft 14 can be inserted is formed in each of the upper plate 81 and the lower plate 82. One end of the second shaft 80 has a protruding piece with an external thread, and a retaining nut 87 is screwed to the protruding piece. The retaining nut 87 has a larger diameter than the through holes 84a and 84b, and when the second shaft 80 is attached to the second hole 15b of the bracket 15 through either one of the through holes 84a and 84b, the retaining nut 87 is engaged with the upper plate 81, preventing the second shaft 80 from falling out.

The axis of each of the through holes 84a, 84b forms an angle θ with respect to the axis of the first hole 15a and the axis of the insertion hole 88 on a virtual plane perpendicular to the axes of each of the through holes 84a, 84b and the first hole 15a. This angle θ may be, for example, 10° or more and 20° or less, or may be 15°. This allows the bracket 15 and the blade 3 connected thereto to be angularly displaced around the axis of the first shaft 14 between a first position where one through hole 84a communicates with the second hole 15b and a second position where the other through hole 84b communicates with the second hole 15b, depending on the size of the tire T. The second shaft 80 is inserted into the second hole 15b through one of the through holes 84a, 84b that communicates with the second hole 15b, preventing angular displacement of the bracket 15 and the blade 3. The orientation of the bracket 15 and the blade 3 can be adjusted to an appropriate angle for the tire T, and the bead portion TB can be pressed without the blade 3 coming into contact with the rim portion.

The second connecting portion 12 has an attachment piece 16 fixed to the bracket 15 by welding, a first guide member 17 to which the attachment piece 16 is fixed, for example, by welding, and having an axial hole 17a, a guide shaft 18 inserted into the axial hole 17a of the first guide member 17, a second guide member 19 fixed to one end of the guide shaft 18, for example, by welding, and having a radial hole 19a, and a bracket 25 connected to the radial hole 19a of the second guide member 19 by a bolt 121 and a nut 21, and fixed to the back surface of the blade 3, for example, by welding.

The blade 3 is made of a steel or stainless steel plate that forms part of a cylinder curved with a curvature that corresponds to the standard shape of the bead portion TB of a tire T of a passenger vehicle, and one side edge of the blade 3 is provided with a tip portion 3a that is tapered and extends in a roughly arc shape.

The blade 3 is connected to the free end 5a of the arm 5 by the first connecting part 11 so that it can be angularly displaced around the axis L2 parallel to the rotation axis L31, and is connected to the first connecting part 11 by the second connecting part 12 so that it can be angularly displaced around the horizontal axis L3. Therefore, even if the size of the tire T is different, the tip part 3a of the blade 3 can be accurately positioned near the rim part of the bead part TB and can press against the bead part TB.

Figure 6A is a pneumatic circuit diagram showing the configuration of the flow path configuration unit 10, Figure 6B is a pneumatic circuit diagram for explaining the first flow path of the flow path configuration unit 10, Figure 6C is a pneumatic circuit diagram for explaining the second flow path of the flow path configuration unit 10, and Figure 6D is a pneumatic circuit diagram for explaining the third flow path of the flow path configuration unit 10. First, the flow path configuration unit 10 will be described with reference to Figure 6A. The flow path configuration unit 10 includes a first operating valve V1, a second operating valve V2, a first switching valve V3, a second switching valve V4, a first check valve V6, and a second check valve V7. The first operating valve V1 is composed of a 5-port 2-position switching valve having a push button 85 for switching from the first position to the second position and a spring S for returning from the second position to the first position. The second operating valve V2 is composed of a 5-port 3-position switching valve, and automatically returns to a neutral position when not operated. The first switching valve V3 is a 5-port 3-position switching valve with two pilot ports c1 and c2, and automatically returns to the neutral position if no pilot pressure is applied to the pilot ports c1 and c2. The second switching valve V4 is a 3-port 2-position switching valve with one pilot port c1 and a return spring S. The pressure reducing valve V5 is a pressure reducing valve with a relief valve. When the second switching valve V4 is in the first position, the first input port a1 is closed by inserting a tapered plug, and the release of compressed air is blocked even if the third pipe m3 is connected to the second input port a2.

The flow path configuration unit 10 is configured so that, by the operator operating the push button 85 of the operation unit 9, it can be switched to one of the following flow paths: a first flow path (see FIG. 6B) that guides compressed air to the first port 8a of the double-acting pneumatic cylinder CY1 and opens the second port 8b to the atmosphere; a second flow path (see FIG. 6C) that guides compressed air to the second port 8b and opens the first port 8a to the atmosphere; and a third flow path (see FIG. 6D) that guides compressed air to the second port 8b and reduces the pressure of the compressed air before directing it to the first port 8a.

In the non-operated state where the push button 85 of the first operating valve V1 is not operated, as shown in FIG. 6A, the first operating valve V1 is in the first position, the first line m1 to which compressed air is supplied from the compressed air pressure source 6 is connected to the third line m3, and the compressed air in the first line m1 is supplied to the third line m3. The second input port a2 of the compressed air in the third line m3 is closed because the second operating valve V2 is in the neutral position. In this state, the piston rod 7 is stopped by the double-acting pneumatic cylinder CY1.

When the operator operates the operation lever 86 of the operation unit 9 in the direction of the arrow d1, the second operation valve V2 moves from the neutral position to the first position to become the first flow path, as shown in Fig. 6B. Therefore, the compressed air supplied from the compressed air pressure source 6 to the first pipe m1 is led to the third pipe m3 via the second input port a2 and the first output port b1 of the first operation valve V1 in the first position, and is led to the seventh pipe m7 via the second input port a2 and the first output port b1 of the second operation valve V2 in the first position. The compressed air in the seventh pipe m7 is led to one pilot port c1 of the first switching valve V3, moving the first switching valve V3 from the neutral position to the first position. Therefore, compressed air from the compressed air pressure source 6 is guided from the second pipe m2 through the second input port a2 and the first output port b1 of the first switching valve V3 in the first position to the ninth pipe m9, and is supplied to one of the pressure chambers from the first port 8a of the double-acting pneumatic cylinder CY1. The air in the other pressure chamber is discharged from the second port 8b to the tenth pipe m10, the second output port b2, and the third input port a3 into the atmosphere. This moves the piston rod 7 in the first direction A1, and a space is formed between the blade 3 and the main body 2 for carrying the tire T. The tire T is carried into this space by the operator.

Next, when the operator operates the operating lever 86 of the operating unit 9 in the direction of the arrow d2, the second operating valve V2 moves from the neutral position to the second position to become the second flow path, as shown in Fig. 6C. Therefore, the compressed air supplied from the compressed air pressure source 6 to the first pipe m1 is guided to the third pipe m3 via the second input port a2 and the first output port b1 of the first operating valve V1 in the first position, and is guided to the eighth pipe m8 via the second input port a2 and the second output port b2 of the second operating valve V2 in the second position. The compressed air in the eighth pipe m8 is guided to the other pilot port c2 of the first switching valve V3, moving the first switching valve V3 from the neutral position to the second position. Compressed air from the compressed air pressure source 6 is guided from the second pipe m2 through the second input port a2 and the second output port b2 of the first switching valve V3 in the second position to the tenth pipe m10, and is supplied to the other pressure chamber from the second port 8b of the double-acting pneumatic cylinder CY1. The air in one pressure chamber is dissipated to the atmosphere from the first output port b1 and the first input port a1 of the first switching valve V3 through the first port 8a to the ninth pipe m9. This causes the piston rod 7 to move in the direction of the arrow A2, and the blade 3 presses the bead portion TB, separating the bead portion TB from the rim portion.

The operator can recognize that the bead portion TB is about to separate from the rim portion by a subtle change in the pressing force of the blade 3 on the bead portion TB. When the operator recognizes that the bead portion TB is beginning to separate from the rim portion, the operator presses the push button 85. As a result, as shown in FIG. 6D, the first control valve V1 moves from the first position to the second position, and the second switching valve V4 moves from the first position to the second position. The second control valve V2 automatically returns to the neutral position. Therefore, the compressed air of the compressed air pressure source 6 is led from the first pipe m1 through the second input port a2 and the second output port b2 of the first control valve V1 in the second position to the fourth pipe m4. The compressed air in the fourth pipe m4 is led to the fifth pipe m5 and the sixth pipe m6. The compressed air from the fifth line m5 passes through the tenth line m10 and is supplied to the other pressure chamber from the second port 8b of the double-acting pneumatic cylinder CY1. The compressed air from the sixth line m6 is decompressed by the pressure reducing valve V5, and is guided to the eleventh line m11 through the second input port a2 and the first output port b1 of the second switching valve V4 in the second position, and is supplied to one of the pressure chambers from the first port 8a of the double-acting pneumatic cylinder CY1.

When the push button 85 is pressed in this way, compressed air is supplied to the other pressure chamber of the double-acting pneumatic cylinder CY1, and reduced pressure compressed air is supplied to one pressure chamber, so that even if the bead portion TB separates from the rim portion, the movement of the piston rod 7 in the direction of the arrow A2 is braked, and impact is suppressed.

The operation unit 9 includes the first operation valve V1 described above. As described above, the flow path configuration unit 10 is configured to be able to switch to any one of the first flow path shown in FIG. 6B, the second flow path shown in FIG. 6C, and the third flow path shown in FIG. 6D by the operator operating the operation lever 86 in the direction of the arrow d1. In the non-operation state in which the push button 85 is not operated, the first operation valve V1 is located in the first position, the first pipe m1 to which compressed air is supplied from the compressed air pressure source 6 is connected to the second input port a2 of the first operation valve V1, and the compressed air in the first pipe m1 is supplied from the first output port b1 to the third pipe m3. At this time, the second operation valve V2 is in the neutral position, and the first switching valve V3 has also returned to the neutral position. Compressed air is not supplied to either the first port 8a or the second port 8b of the double-acting pneumatic cylinder CY1, and no operating pressure is applied. In this state, the operator can grasp the operating lever 13 and move the blade 3 to perform positioning work so that the tip 3a of the blade 3 is located near the rim portion of the bead portion TB.

Referring again to FIG. 2, when the operator grasps the operating lever 13 to move the blade 3, the movement is transmitted to the piston rod 7 via the arm 5. When the operator operates the operating lever 86 in the direction of the arrow d1 to move the second operating valve V2 from the neutral position to the first position, the compressed air in the first pipe m1 flows into the third pipe m3 via the second input port a2 and the first output port b1 of the first operating valve V1. The compressed air in the third pipe m3 is supplied to the seventh pipe m7 via the second input port a2 of the second operating valve V2 located in the first position and the first output port b1. The first pilot port c1 of the first switching valve V3 is pressurized by the compressed air in the seventh pipe m7, and the first switching valve V3 is moved from the neutral position to the first position. As a result, the compressed air in the second pipe m2 is supplied to the ninth pipe m9 via the second input port a2 and the first output port b1. Compressed air in the ninth pipe m9 is supplied to one of the pressure chambers via the first port 8a of the double-acting pneumatic cylinder CY1, and the piston rod 7 is driven in the first direction A1. This displacement of the piston rod 7 in the first direction A1 puts the piston rod 7 in a state in which it can tolerate the displacement of the blade 3 in a direction away from the main body 2, so that the blade 3 is moved in a direction away from the main body 2 (in the direction of the arrow A1), and a storage space for the tire T with the wheel W attached is formed to the side of the main body 2. The above-mentioned permissible state refers to a state in which an operator can manually move the blade 3 away from the main body 2 in the direction of the arrow A1.

When a tire T with a wheel W mounted thereon is carried upright into the storage space on the side of the main body 2 by an operator for tire replacement and the push button 85 is pressed, the first operating valve V1 moves from the first position to the second position, and the first pipe m1 is connected to the second input port a2. The compressed air supplied to the second input port a2 is supplied from the second output port b2 to the fourth pipe m4. The compressed air in the fourth pipe m4 is supplied to the other pressure chamber from the second port 8b of the double-acting pneumatic cylinder CY1 via the fifth pipe m5 and the tenth pipe m10. As a result, the piston rod 7 moves in the second direction A2, and the bead portion TB is pressed by the tip portion 3a of the blade 3, so that the bead portion TB can be separated from the rim portion. At this time, the compressed air in the fourth line m4 is also supplied to the pilot port c1 of the second switching valve V4, so the second switching valve V4 is moved from the first position to the second position. Therefore, the compressed air in the sixth line m6 is reduced in pressure by the pressure reducing valve V5 and is supplied to the eleventh line m11 via the second input port a2 and the first output port b1. Since the compressed air in one pressure chamber of the double-acting pneumatic cylinder CY1 has a lower pressure than the compressed air supplied to the other pressure chamber, the piston rod 7 is allowed to move in the second direction A2 while suppressing abrupt displacement of the piston rod 7 in the second direction A2, braking the movement of the piston rod 7 in the second direction A2 and mitigating the impact that occurs when the bead portion TB comes off the rim portion.

Figure 7 is a graph showing the pneumatic reaction force R1 and spring reaction force R2 from a confirmation test of the impact mitigation effect, and Figure 8 is a cross-sectional view showing the single-acting pneumatic cylinder CY2 used to measure the spring reaction force R2. In Figure 7, the vertical axis indicates the magnitude of the reaction force, and the horizontal axis indicates the displacement of the blade 3. In order to confirm the impact mitigation effect against the impact when the bead portion TB is separated from the rim portion by the bead separating device 1 of this embodiment, the case where the above-mentioned double-acting pneumatic cylinder CY1 was used was used as an example, and the case where the single-acting pneumatic cylinder CY2 of Figure 8 was used instead of the double-acting pneumatic cylinder CY1 was used as a comparative example, and the magnitude of the reaction force against the displacement amount y of the blade 3 was measured. The single-acting pneumatic cylinder CY2 includes a cylinder case 120 with an inner diameter of 200 mm, a piston 22 housed in the cylinder case 120 and dividing the space inside the cylinder case 120 into two pressure chambers 21a and 21b, a piston rod 23 with one end fixed to the piston 22, and a buffer spring 24 housed in one pressure chamber 21a and biasing the piston 22 in the first direction A1. The buffer spring 24 is a compression coil spring with a spring constant of 0.753 kgf/mm and a free length of 270 mm.

The above air pressure reaction force R1 is a value calculated by multiplying the air pressure entering from the port by the pressure-receiving area of the piston 22. The spring reaction force R2 is a value calculated by determining the positions of the piston 22 corresponding to the multiple positions of the blade 3 on the drawing, and multiplying the compression amount of the buffer spring 24 at each position by the spring constant. As shown in FIG. 7, the spring reaction force R2 by the buffer spring 24 decreases as the displacement amount of the blade 3 increases, whereas the air pressure reaction force R1 by the compressed air is constant regardless of the position of the blade 3. Therefore, according to the double-acting pneumatic cylinder CY1 of this embodiment using the air pressure reaction force R1, a certain impact mitigation effect can be obtained when the bead portion TB separates from the rim portion, regardless of the position of the blade 3.

Compressed air at a pressure of 0.2 MPa was supplied to the first port 8a of the double-acting pneumatic cylinder CY1 used in the embodiment, and compressed air at a pressure of 1.0 MPa was supplied to the second port 8b. The reaction force of the piston rod 23 was measured, and it was confirmed that even if the bead portion TB separated from the rim portion while being pressed by the blade 3, the impact of the blade 3 suddenly displacing in the pressing direction was mitigated regardless of the pressing position of the blade 3.

Figure 9 is a front view showing an example of a tire mounting/removal device 31 equipped with a bead separating device 1, and Figure 10 is a plan view of the tire mounting/removal device 31. The tire mounting/removal device 31 is used to replace a tire T mounted on a wheel W with a new tire T. The tire mounting/removal device 31 basically includes the above-mentioned bead separating device 1, a bead portion guiding device A, a bead press device B, a first tire holding device C, and a second tire holding device D.

The bead guide device A includes a rotary table 34 on which a wheel W is mounted, which detachably holds the lower rim of the wheel W and is driven to rotate in the direction of the arrow E around the rotation axis L31, a lifting arm 35 that is movable upward and downward, a bead guide member 36 that is attached to the lower end of the lifting arm 35, a horizontal arm 37 that holds the lifting arm 35 and is movable in the front-rear direction approaching/moving away from the rotation axis L31, and a support pillar 38 that pivots about its lower end in a direction approaching/moving away from the rotation axis L31.

The rotating table 34 is equipped with a chuck means 70 that detachably holds the wheel W that is placed coaxially with the rotation axis L31. The chuck means 70 has four chuck jaws 71 that are axially symmetrical with respect to the rotation axis L31, and each chuck jaw 71 is mounted on a slider 73 and driven by a double-acting pneumatic cylinder CY3 to move toward and away from each other. These chuck jaws 71 clamp the lower rim portion of the placed wheel W from the radially outward direction, and can hold the wheel W on the same axis as the rotation axis L31. When the chuck jaws 71 are displaced away from each other, the clamped state of the wheel W is released, and the wheel W can be removed from the rotating table 34.

On the base 83 of the rotating table 34, there are provided a support tilt pedal Ps for tilting/standing up the support 38, a chucking pedal Pc for opening/closing the slider 73 and fixing/releasing the wheel W, a push button 85 for pressing the blade 3 of the bead separating device 1 in the bead pressing direction, i.e., in the direction approaching the base 83, and releasing the pressing force, and a rotation command pedal Pr for instructing the forward/reverse operation of the rotating table 34.

The bead guide member 36 is a mounting member that is detachably attached to the lower end of the lifting arm 35 made of steel or stainless steel by means of bolts or the like, and is equipped with a bead support portion 41 that supports the upper bead portion TB from below and guides the upper bead portion TB upward as it becomes downstream in the rotation direction E while engaging with the upper rim portion of the wheel W of the tire T set on the rotary table 34, and an insertion portion 42 that is inserted between the upper rim portion and the upper bead portion TB that is in close contact with the upper rim portion. The bead support portion 41 is parallel to an imaginary horizontal plane perpendicular to the rotation axis L31. The insertion portion 42 is formed in a rod shape that tapers toward the downstream side of the rotation direction E of the rotary table 34.

The bead press device B includes a bead press arm 50 that is provided on the rotary table 34 so as to be displaceable in an upward direction away from the rotary table 34 and in a downward direction approaching the rotary table 34, and is provided so as to be displaceable along a horizontal axis L34 perpendicular to the rotation axis L31 of the rotary table 34 in a forward direction approaching the rotation axis L31 and in a backward direction away from the rotation axis L31, a bead roller 51 that is held at one end 8 (see FIG. 10) of the bead press arm 50 in the longitudinal direction and disposed closer to the rotation axis L31, and is provided so as to be rotatable while pressing down the upper bead portion TB of the tire T mounted on the rotary table 34, and an arm holding unit 52 that holds the bead press arm 50 so as to be movable in the longitudinal direction. The arm holding unit 52 may be realized by a pneumatic linear cylinder or a linear slider.

The bead roller 51 has a peripheral pressing surface 51a in the shape of a truncated cone, the diameter of which decreases as it moves away from the rotation axis L31, and is mounted on a virtual plane of the rotation axis L31, including the axis L34 of the bead press arm 50 and the rotation axis L31 of the rotating table 34, with its bottom surface facing the rotation axis L31, and is rotatable about an axis L33 that is inclined in a direction moving away from the rotation axis L31 as it moves downward.

Such a bead roller 51 can press the upper bead portion TB of the tire T mounted on the wheel W from above with a part of the pressing surface at a position downstream of the position where the bead guide member 36 is disposed in the rotation direction E at a predetermined angle φ. The tire T is, for example, a run-flat tire with high rigidity. The predetermined angle φ is selected to be 30° or more and less than 90° (30°≦φ<90°) downstream of the rotation direction E of the rotary table 34 from a virtual plane including the rotation axis L31 and the position where the bead guide member 36 is disposed. In other words, the bead roller 51 is provided in a range where the angle formed by the first virtual plane including the rotation axis L31 and the position where the bead guide member 36 is disposed and the second virtual plane including the rotation axis L31 and the pressing position by the bead roller 51 is 30° or more and less than 90°.

The first tire pressing device C includes a lifting means 61 provided adjacent to the rotary table 34 and having a lifting body 60 that moves up and down along a moving path parallel to the rotation axis L31 of the rotary table 34, an arm 62 rotatably connected to the lifting body 60 of the lifting means 61 about an axis L41 parallel to the rotation axis L31 of the rotary table 34, an arm 63 rotatably connected to the arm 62 about an axis L40 parallel to the rotation axis L31 of the rotary table 34 and connected above the arm 62 about the axis L40, an arm 64 rotatably connected to the arm 63 about an axis L35 below the arm 63, and a tire pressing member 65 provided on the arm 64 so as to be movable along the arm 64. The lifting means 61 is realized by a double-acting pneumatic cylinder.

The tire pressing member 65 has a plate-shaped pressing portion 66 that presses the tire T from above in an area downstream in the rotational direction E from the position where the bead roller 51 is arranged and upstream in the rotational direction E from the position where the bead guide member 36 is arranged. With the tire T pressed from above by this pressing portion 66, the arms 62, 63, and 64 are angularly displaced and can move freely in accordance with the rotation of the tire T.

The tire holding member 65 has the plate-shaped pressing portion 66 described above, a side wall portion 67 rising upward from one side of the pressing portion 66, and a boss portion 68 formed integrally with the side wall portion 67 and the pressing portion 66, into which the lower end of a connecting shaft 69 that connects the arm 64 and the tire holding member 65 is inserted and which is connected to the side wall portion 67 so as to be rotatable about the axis L36 of the connecting shaft 69. Such a tire holding member 65 may be made of a material that is strong, has excellent impact resistance and abrasion resistance, and has good sliding properties with respect to the tire T, such as polycarbonate.

The second tire pressing device D has a pressing body 53 that moves following the rotation of the tire T, and presses the upper sidewall portion of the tire T downstream of the bead roller 51 in the direction of rotation E of the tire T and upstream of the pressing part 66 of the first tire pressing device C in the direction of rotation E of the tire T. The pressing body 53 is a truncated cone-shaped member with a diameter enlarged downward, made of, for example, polypenco acetal manufactured by Nippon Polypenco Co., Ltd., made from acetal copolymer and homopolymer as raw materials. The pressing body 53 presses the upper sidewall portion of the tire T by abutting the lower surface of the truncated cone-shaped member. The second tire pressing device D is used when mounting the tire T on the wheel W.

The second tire pressing device D has an arm 75 rotatably connected around an axis L37, an arm 76 rotatably connected to the arm 75 around an axis L38 parallel to the axis L37, and a drive unit 74 at the tip of the arm 76 that moves up and down along the axis L38. The pressing body 53 is rotatably arranged around an axis L39 parallel to the axis L38. The axes L37 to L39 can also be inclined in a direction away from the rotation axis L31 as they move upward from the rotation axis L31. In this way, when the pressing body 53 is not pressing the tire T, it moves in a direction away from the rotation axis L31, so that the pressing body 53 can be prevented from accidentally contacting the bead press device B and the like, and the upper bead portion TB can be separated from the rim portion of the wheel W.

With the tire T already attached to the wheel in an upright position, the blade 3 of the bead separating device 1 is set at a position about 10 mm to 20 mm away from the wheel W. When the push button 85 of the bead separating device 1 is pressed in this state, the blade 3 moves in the second direction A2 approaching the tire T, pressing the upper bead portion TB of the tire T and dropping the upper bead portion TB into the drop portion of the wheel W. Next, the tire T is turned over and the blade 3 is set at a position about 10 mm to 20 mm away from the wheel W. When the push button 85 of the bead separating device 1 is pressed in this state, the blade 3 moves in the second direction A2 approaching the tire T, pressing the lower bead portion TB of the tire T and dropping the lower bead portion TB into the drop portion of the wheel W. After this, the tire T is placed on the rotating table 34 and the tire replacement work is performed.

In a tire replacement operation, an operator places the tire T already attached to the wheel, with the bead portion TB having been separated from the rim portion, on the rotating table 34. Next, the operator depresses the chucking pedal Pc, so that the lower rim portion is gripped by the chuck claws 71 and the wheel W is fixed to the rotating table 34. The operator then depresses the rotation command pedal Pr to rotate the tire T already attached to the wheel about the rotation axis L31, and the bead guide member 36 separates the upper bead portion TB from the upper rim portion of the wheel W. The lower sidewall portion of the tire T is then pushed up by the push-up roller 78, allowing the tire T to be removed from the wheel W.

Next, the worker places a new tire T on the wheel W, and while holding down the upper sidewall of the tire T with the tire pressing member 65, hooks the upper bead portion TB onto the bead guide member 36. The worker then depresses the chucking pedal Pc described above to rotate the tire T together with the wheel W around the rotation axis L31. As a result, the upper bead portion TB is guided below the upper rim portion by the bead guide member 36, and the new tire T is mounted on the wheel W.

When the new tire T is mounted on the wheel W, the worker depresses the rotation command pedal Pr to stop the rotation of the rotary table 34, and then depresses the chucking pedal Pc to move the chuck claws 71 away from the lower rim of the wheel W and release the chuck state of the wheel W. The worker then removes the tire T already attached to the wheel that has been replaced with the new tire T from the rotary table 34, completing the tire replacement work.

According to the present invention, one of the first flow path, the second flow path, and the third flow path is selected by the operating unit 9. When the operator operates the operating unit 9 to select the third flow path just before the bead portion TB separates from the rim portion, compressed air is supplied to the second port 8b of the double-acting pneumatic cylinder CY1, and compressed air at reduced pressure is supplied to the first port 8a of the double-acting pneumatic cylinder CY1. As a result, the movement of the piston rod 7 in the second direction A2 is braked by the pressure of the reduced pressure compressed air, sudden displacement of the blade 3 in the second direction A2 is suppressed, and damage caused by contact of the blade 3 with the rim portion of the wheel W is suppressed.

Furthermore, according to the present invention, the blade 3 is connected by the first connecting portion 11 so as to be capable of angular displacement about an axis parallel to the rotation axis L31, so that the pressing position of the blade 3 against the bead portion TB can be adjusted about an axis parallel to the rotation axis L31 according to the size of the tire T mounted on the wheel W. Therefore, the pressing position can be adjusted so that the tip portion 3a of the blade 3 is positioned near the rim portion of the bead portion TB with high precision, and the blade 3 can be positioned and arranged at an appropriate pressing position, thereby enabling the bead portion TB to be separated from the rim portion more reliably.

Furthermore, according to the present invention, the first connecting portion 11 is connected by the second connecting portion 12 so that it can be angularly displaced about a horizontal axis, so that the pressing position of the blade 3 against the bead portion TB can be adjusted about the horizontal axis according to the size of the tire T mounted on the wheel W. Therefore, the pressing position of the blade 3 can be adjusted to be near the rim portion of the bead portion TB with high precision, and the blade 3 can be positioned and arranged at an appropriate pressing position, which allows the bead portion TB to be separated from the rim portion more reliably.

In addition, according to the present invention, the pressure of the compressed air introduced into the first port 8a is reduced by the pressure reducing valve V5, so that the set pressure of the pressure reducing valve V5 can be easily set to an optimal value according to the hardness of the bead portion TB, and the occurrence of an impact when the bead portion TB separates from the rim portion can be more reliably suppressed.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various modifications and improvements are possible without departing from the spirit of the present invention. It goes without saying that all or part of the components of each of the above-mentioned embodiments can be combined appropriately and to the extent that there are no contradictions.

REFERENCE SIGNS LIST 1 Bead separating device 2 Main body 3 Blade 5 Arm 5a Free end 5b Base end 6 Compressed air pressure source 7 Piston rod 8a First port 8b Second port 9 Operation section 10 Flow path configuration section 11 First connection section 12 Second connection section A1 First direction A2 Second direction CY1 Double-acting pneumatic cylinder L1 Axis L31 Rotation axis m1-m11 First pipe line-Eleventh pipe line T Tire mounted on wheel TB Bead section V1 First operation valve V2 Second operation valve V3 First switching valve V4 Second switching valve V5 Pressure reducing valve V6 First check valve V7 Second check valve

Claims (3)

A main body portion including a rotary table that holds a wheel with a tire and is rotatable about a rotation axis;
an arm having a free end and a base end connected to the main body portion so as to be rotatable about an axis parallel to the rotation axis;
a blade provided on the free end of the arm for pressing a bead portion of a tire of a tire-mounted wheel arranged in an upright state on the side of the main body;
A compressed air pressure source that generates compressed air;
a double-acting pneumatic cylinder including a piston rod that moves in a first direction or a second direction opposite to the first direction and is connected to the arm, a first port to which the compressed air is supplied when the piston rod is moved in the first direction, and a second port to which the compressed air is supplied when the piston rod is moved in the second direction;
a flow path configuration unit that is switchable between a first flow path that guides the compressed air to the first port and opens the compressed air from the second port to the atmosphere, a second flow path that guides the compressed air to the second port and opens the compressed air from the first port to the atmosphere, and a third flow path that guides the compressed air to the second port and reduces the pressure of the compressed air before directing it to the first port;
a pressure reducing valve that is interposed in a flow path connecting the compressed air pressure source and the first port and reduces the pressure of the compressed air introduced into the flow path;
and an operation unit capable of selecting any one of the first flow path, the second flow path, and the third flow path. The bead breaking device according to claim 1, characterized in that it includes a first connecting part that connects the blade to the free end of the arm so that the blade can be angularly displaced about an axis parallel to the rotation axis. The bead separating device according to claim 2, characterized in that it includes a second connecting part that connects the blade to the first connecting part so that the blade can be angularly displaced about a horizontal axis.