Roll press device

Abstract

To provide a roll press device capable of miniaturizing the whole device without lowering compression load to a workpiece.SOLUTION: Provided is a roll press device for conveying a workpiece W while applying compression load to the workpiece between a pair of rolls which are vertically provided and both ends of which are rotatably held by bearings, where a plurality of pairs of rolls 4, 5, and 6 are provided so as to be shifted in a width direction of the workpiece W.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a roll press device that applies a compressive load to a workpiece by means of a pair of rolls disposed above and below it. [Background technology]

[0002] Patent Document 1 describes a roll press device that compresses a thin film material by passing the thin film material between a pair of upper and lower rolls. The upper and lower rolls in this roll press device are supported at both ends by a main bearing and a bend bearing, respectively. The roll press device also includes a bend mechanism that applies a bend load to the bend bearing in the direction opposite to the direction of deflection of the roll when compressing the thin film material. This bend mechanism is composed of a cylinder, a piston that reciprocates within the cylinder, a piston rod integrated with the piston, and a link portion that is provided at the tip of the piston rod and applies the piston load to the bend bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7176154 Summary of the Invention [Problem to be solved by the invention]

[0004] A roll press device, such as that described in Patent Document 1, which performs compression or rolling by passing a thin-film workpiece between a pair of rolls, uses rolls that correspond to the size of the workpiece. That is, if the width of the workpiece is wide, the axial length of the roll becomes long. Also, in roll press processing, a load is usually distributed over the entire axial length of the roll. Therefore, as the axial length of the roll increases, the load that must be generated by the bending mechanism also increases, which may result in an increase in the size of the bending mechanism and, ultimately, the size of the roll press device.

[0005] The present invention was devised with an eye on the above-mentioned technical problems, and aims to provide a roll press device that can reduce the size of the entire device without reducing the compressive load on the workpiece. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a roll press device that transports a workpiece while applying a compressive load to the workpiece between a pair of rolls that are arranged one above the other and are rotatably held at both ends by bearings, and is characterized in that multiple pairs of rolls are arranged offset in the width direction of the workpiece.

[0007] In addition, in this invention, the multiple roll pairs are arranged with a shift in the direction of travel of the workpiece and the width direction of the workpiece, and the roll pair upstream in the direction of travel of the workpiece and the roll pair downstream in the direction of travel of the workpiece may overlap at least partially in the width direction of the workpiece.

[0008] In addition, in this invention, the pair of rolls may include an upper roll that abuts the upper surface of the workpiece and a lower roll that abuts the lower surface of the workpiece, and a recess may be formed on the axial end surface of at least one of the upper roll and the lower roll to reduce the rigidity of the end of the one roll.

[0009] The present invention may further comprise a bearing for rotatably holding the one roll, and at least a portion of the bearing may be inserted into the recess. [Effects of the Invention]

[0010] In the roll press apparatus of the present invention, a plurality of roll pairs that apply a compressive load to a workpiece are provided, offset in the width direction of the workpiece. That is, the axial length of the roll pairs is shorter than in a configuration in which a single roll pair applies a compressive load across the entire width direction of the workpiece. This allows the distance between the bearings that support the roll pairs to be shorter. Therefore, the shorter axial distance allows the second moment of area of ​​the roll pair to be reduced, i.e., the outer diameter of the roll pair to be reduced. As a result, the roll pairs and the bearings that support the roll pairs can be made smaller without reducing the compressive load on the workpiece, and ultimately the roll press apparatus can be made smaller. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view illustrating an example of a main part of a roll press device according to an embodiment of the present invention. [Figure 2] 1A and 1B are diagrams illustrating an example of a housing of a roll press device, in which (a) is a perspective view thereof, (b) is a side view thereof, and (c) is a cross-sectional view taken along line ii in (b). [Figure 3] 10A and 10B are diagrams for explaining the load acting on the roll and the amount of deflection of the roll when crimping a workpiece. [Figure 4] FIG. 2 is a cross-sectional view showing an example of a roll having recesses formed on both end surfaces. [Figure 5] FIG. 10 is a cross-sectional view showing an example in which a part of a bearing is inserted into a recess. [Figure 6] 10 is a cross-sectional view showing an example in which a part of the sealing member is inserted into a recess. FIG. [Figure 7] FIG. 10 is a diagram showing the results of an analysis of the amount of deflection in the axial direction of the roll when parts of bearings are inserted into recesses formed on both end faces of the roll. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of specific embodiments of the present invention and are not intended to limit the scope of the present invention.

[0013] A roll press device according to an embodiment of the present invention is configured to press a workpiece using a plurality of roll pairs. Fig. 1 is a perspective view illustrating an example of the main components of the configuration. Fig. 1 shows an example of a roll press device that presses a current collector 1, a positive electrode active material 2 provided on one side of the current collector 1, and a negative electrode active material 3 provided on the other side of the current collector 1, which constitute an electrode pair of a lithium-ion battery.

[0014] The current collector 1 is formed of a metal foil such as copper (Cu), nickel (Ni), aluminum (Al), iron (Fe), or titanium (Ti). The positive electrode active material 2 is mainly composed of a material such as cobalt, nickel, or manganese, or phosphorus (P), iron (Fe), or lithium (Li). The negative electrode active material 3 is mainly composed of a carbon-based material such as graphite or lithium titanate.

[0015] The current collector 1 is formed in a strip shape and is continuously drawn out from a roll (not shown), and one surface of the strip-shaped current collector 1 is coated with a positive electrode active material 2, and similarly, the other surface of the strip-shaped current collector 1 is coated with a negative electrode active material 3, thereby forming a strip-shaped electrode. The strip-shaped electrode thus formed (hereinafter, this strip-shaped electrode will be referred to as workpiece W) is conveyed to a roll press device while being positioned in the width direction.

[0016] The workpiece W formed as described above is configured to be pressed by multiple roll pairs. In the example shown in FIG. 1 , a first roll pair 4 composed of a first roll 4a contacting the upper surface of one side of the workpiece W in the width direction and a second roll 4b contacting its lower surface, and a second roll pair 5 composed of a third roll 5a contacting the upper surface of the other side of the workpiece W in the width direction and a fourth roll 5b contacting its lower surface, are provided side by side in the width direction of the workpiece W. In addition, a third roll pair 6 composed of a fifth roll 6a contacting the upper surface of a central portion of the workpiece W in the width direction and a sixth roll 6b contacting its lower surface are provided downstream of the first roll pair 4 and the second roll pair 5. These rolls 4a, 4b, 5a, 5b, 6a, and 6b are formed to be shorter than the width of the workpiece W. The first roll 4a, the third roll 5a, and the fifth roll 6a correspond to the "upper rolls" in this embodiment of the invention, and the second roll 4b, the fourth roll 5b, and the sixth roll 6b correspond to the "lower rolls" in this embodiment of the invention.

[0017] Specifically, one end of the first roll pair 4 extends outward beyond one edge of the workpiece W in the width direction, and the other end of the second roll pair 5 extends outward beyond the other edge of the workpiece W in the width direction. The first roll pair 4 and the third roll pair 6 are arranged to overlap partially in the width direction of the workpiece W, and the second roll pair 5 and the third roll pair 6 are arranged to overlap partially in the width direction of the workpiece W. More specifically, the press centers of the roll pairs 4, 5, and 6 (the central portions of the axial directions of the roll pairs 4, 5, and 6) are arranged to be offset in the width direction of the workpiece W. In other words, as the workpiece W advances, the entire width direction of the workpiece W is sandwiched between the first roll pair 4, the second roll pair 5, and the third roll pair 6.

[0018] The second roll 4b, the fourth roll 5b, and the sixth roll 6b are provided so as to be movable up and down by a lifting mechanism described later, and the gap between the first roll 4a and the second roll 4b, the gap between the third roll 5a and the fourth roll 5b, and the gap between the fifth roll 6a and the sixth roll 6b are adjusted to be narrower than the thickness of the workpiece W before pressing. Specifically, the gap between the first roll 4a and the second roll 4b, the gap between the third roll 5a and the fourth roll 5b, and the gap between the fifth roll 6a and the sixth roll 6b are set so that, as the workpiece W moves through these gaps, the film thickness of the positive electrode active material 2 and the negative electrode active material 3 coated on the workpiece W is made uniform, or the density of these active materials 2 and 3 is adjusted to a predetermined density, or the surface of the workpiece W is made smooth, or the pressure required to press the positive electrode active material 2 or the negative electrode active material 3 onto the current collector 1 acts on the workpiece W.

[0019] Each of these rolls is provided with a support shaft that protrudes in the axial direction and is rotatably supported by a bearing. Specifically, the support shafts protruding from both ends of the first roll 4a are rotatably supported by the first bearing 7 and the second bearing 8, and the support shafts protruding from both ends of the second roll 4b are rotatably supported by the third bearing 9 and the fourth bearing 10. Furthermore, the support shafts protruding from both ends of the third roll 5a are rotatably supported by the fifth bearing 11 and the sixth bearing 12, and the support shafts protruding from both ends of the fourth roll 5b are rotatably supported by the seventh bearing 13 and the eighth bearing 14. Furthermore, the support shafts protruding from both ends of the fifth roll 6a are rotatably supported by the ninth bearing 15 and the tenth bearing 16, and the support shafts protruding from both ends of the sixth roll 6b are rotatably supported by the eleventh bearing 17 and the twelfth bearing 18.

[0020] The roll pairs and bearings described above are housed and held in a housing 19 that constitutes the roll press apparatus. Fig. 2 shows an example of the housing 19, and the housing 19 shown in Fig. 2 is equipped with a first press frame 20, a second press frame 21, and a third press frame 22 that are arranged opposite and next to each other in the traveling direction of the workpiece W. These press frames 20, 21, and 22 are formed with through holes 23 into which the workpiece W is inserted.

[0021] Furthermore, the upper ends of the first press frame 20 and the second press frame 21 are connected by a first connecting member 24, a second connecting member 25, and a third connecting member 26. A first bearing 7 is fixed to this first connecting member 24, a second bearing 8 and a fifth bearing 11 are fixed to the second connecting member 25, and a sixth bearing 12 is fixed to the third connecting member 26. Similarly, the upper ends of the second press frame 21 and the third press frame 22 are connected by a fourth connecting member 27 and a fifth connecting member 28, and a ninth bearing 15 is fixed to this fourth connecting member 27, and a tenth bearing 16 is fixed to the fifth connecting member 28.

[0022] Furthermore, the lower ends of the first press frame 20 and the second press frame 21 are connected by a sixth connecting member 29, and an elevating mechanism 30 is provided between the sixth connecting member 29 and the third bearing 9, the fourth bearing 10, the seventh bearing 13, and the eighth bearing 14, for raising and lowering these bearings. That is, the lifting mechanism 30 moves the bearings up and down, thereby adjusting the gap between the first roll 4a and the second roll 4b and the gap between the third roll 5a and the fourth roll 5b. Note that the lifting mechanism 30 may be provided independently for each pair of bearings or for each bearing, for example, by being configured with an elevating mechanism that raises and lowers the third bearing 9 and the fourth bearing 10, and an elevating mechanism that raises and lowers the seventh bearing 13 and the eighth bearing 14.

[0023] Similarly, the lower ends of the second press frame 21 and the third press frame 22 are connected by a seventh connecting member 31, and an elevating mechanism 32 that raises and lowers the eleventh bearing 17 and the twelfth bearing 18 is provided between the seventh connecting member 31 and the eleventh bearing 17 and the twelfth bearing 18. In other words, the lifting mechanism 32 moves the bearings up and down, thereby adjusting the gap between the fifth roll 6a and the sixth roll 6b. Note that the lifting mechanism 32 may be provided independently for each bearing, for example, by being configured with a lifting mechanism that raises and lowers the eleventh bearing 17 and a lifting mechanism that raises and lowers the twelfth bearing 18.

[0024] These lifting mechanisms 30, 32 may be hydraulic mechanisms that lift the bearings by supplying hydraulic pressure from a hydraulic source (not shown), or may be electric mechanisms that lift the bearings by a motor (not shown).

[0025] Each roll is configured to be rotated at a predetermined rotation speed by a motor. Specifically, each roll is connected to a motor via a joint. In the example shown in FIG. 2, a first motor 34a is connected to one end of the first roll 4a via joint 33a, and a second motor 34b is connected to one end of the second roll 4b via joint 33b. Similarly, a third motor 34c is connected to the other end of the third roll 5a via joint 33c, a fourth motor 34d is connected to the other end of the fourth roll 5b via joint 33d, a fifth motor 34e is connected to the other end of the fifth roll 6a via joint 33e, and a sixth motor 34f is connected to the other end of the sixth roll 6b via joint 33f.

[0026] In the roll press device configured as described above, the clearances of the roll pairs 4, 5, and 6 are adjusted by the lifting mechanisms 30 and 32, and then the workpiece W is transported, whereby the current collector 1, the positive electrode active material 2, and the negative electrode active material 3 constituting the workpiece W are pressed by the roll pairs 4, 5, and 6. FIG. 3 is a diagram illustrating the load acting on the rolls and the amount of deflection of the rolls when pressing the workpiece W. Note that, because the above-described rolls are configured with the same material, axial length, outer diameter, and the like, in the following description, the rolls will be referred to simply as roll R without distinction, and the bearing that holds the roll R will be referred to simply as bearing B without distinction.

[0027] As shown in Figure 3, a reaction force from the workpiece W acts uniformly over the entire length of the roll R. In other words, a uniformly distributed load w acts. In addition, both ends of the roll R are held by bearings B. Therefore, the deflection amount δ of the roll R can be calculated by the following formula (1). δ=(5wL 4 ) / (384EI) …(1)

[0028] Here, in formula (1), L is the distance (m) between the bearings B, E is the longitudinal section modulus (Young's modulus) determined by the material that constitutes the roll R, and I is the second moment of area.

[0029] Moreover, since the roll R is configured by a solid shaft, the second moment of area thereof can be calculated by the following formula (2): where d is the outer diameter of the roll R. I=(πd 4 ) / 64 …(2)

[0030] The distributed load w is a fixed value determined by the load required to compress the workpiece W. Furthermore, the material of the roll R is selected based on cost and other factors. Therefore, the longitudinal section modulus can be said to be a fixed value. Therefore, the deflection amount δ of the roll R is determined by the center distance L and the moment of inertia I (i.e., the outer dimensions of the roll R). Therefore, assuming that the allowable deflection amount δ of the roll R is the same as that of a configuration in which a pair of rolls compresses the workpiece W across the entire width of the workpiece W, by compressing the workpiece W using multiple rolls R divided in the width direction of the workpiece W as described above, the center distance L can be shortened, thereby reducing the moment of inertia I. In other words, the outer diameter of the roll R can be reduced. As a result, by reducing the size of the roll R, the bearings B and lifting mechanisms 30 and 32 that support the roll R can be reduced in size, which ultimately allows for the miniaturization of the roll press apparatus. In other words, it is possible to reduce the size of or omit other mechanisms for suppressing deflection of the roll R, such as bending mechanisms.

[0031] On the other hand, the amount of deflection is greatest in the central portion of the roll R in the axial direction, and the amount of deflection is small in the portion supported by the bearing B. In other words, the compressive load of the workpiece W is large near the bearing B. Therefore, in the above-described roll press device, by providing the bearing B on the inner side in the width direction of the workpiece W, there is a possibility of over-compression compared to a conventional roll press device in which the bearing B is provided at a position away from both sides in the width direction of the workpiece W. For this reason, the roll R in this embodiment of the present invention is configured to reduce the rigidity at both ends. Specifically, as shown in FIG. 4, annular recesses 35 are formed on both end surfaces of the roll R.

[0032] By reducing the rigidity of both ends of the roll R in this way, the reaction force of the workpiece W causes both ends of the roll R to deform so as to narrow the width of the recess 35, and this deformation can absorb the reaction force of the workpiece W. As a result, it is possible to prevent both ends of the roll R from excessively compressing the workpiece W. In other words, it is possible to apply a compressive load uniformly in the width direction of the workpiece W.

[0033] Furthermore, the rigidity of the above-described annular recess 35, determined by its outer diameter dimension (i.e., the inner diameter dimension of the roll R) and the outer diameter dimension of the roll R, may be sufficient to suppress the above-described excessive compression. In other words, when both end portions of the roll R are deformed, a gap may be formed between the inner surface of the roll R and the outer peripheral surface of the support shaft that protrudes from the roll R and is held by the bearing B.

[0034] Therefore, at least a portion of the bearing B may be inserted into recesses 35 formed on both ends of the roll R as shown in Fig. 5. Also, a seal member 36 that prevents oil for maintaining the lubrication of the bearing B from leaking to the workpiece side may be provided on the end face of the bearing B, and in such a case, a portion of the seal member 36 may be inserted into recesses 35 formed on both ends of the roll R as shown in Fig. 6.

[0035] In addition, when the bearing B and the sealing member 36 are inserted into the recess 35 in this manner, a clearance may be provided between the outer peripheral surface of the bearing B and the sealing member 36 and the inner peripheral surface of the roll R (the inner peripheral surface outside the recess 35) to allow for deformation of both ends of the roll R.

[0036] In Fig. 7, the solid line shows the results of CAE analysis of the amount of deflection of the roll R in the axial direction when a portion of the bearing B is inserted into the recessed portions 35 formed on both end surfaces of the roll R. Also, in Fig. 7, the dashed line shows, as a comparative example, the results of CAE analysis of the amount of deflection of the roll R in the axial direction when no recessed portions 35 are formed on both end surfaces of the roll R and the support shafts protruding from both ends are supported by the bearings B. In Fig. 7, the vertical axis represents the amount of deflection, and the horizontal axis represents the position in the axial direction.

[0037] 7, both ends of the roll R are deformed to narrow the width of the recess 35, so that almost no deflection occurs, and by inserting the bearing B into the recess 35, the center distance L is shortened, so that the amount of deflection δ is reduced. In other words, if the amount of deflection at the center of the roll R is allowed to be the same, the external dimensions of the roll R can be made even smaller, and ultimately the roll press device can be made more compact.

[0038] It should be noted that the roll press device in the embodiment of the present invention is not limited to one that presses a strip-shaped workpiece W as described above, but may also be a roll press device that performs rolling processing by sandwiching and pressurizing a plate-shaped or rod-shaped material between roll pairs to deform it into a predetermined shape. Furthermore, the multiple roll pairs may be provided offset in the width direction of the workpiece. For example, one roll pair may be provided upstream in the traveling direction of the workpiece and two roll pairs may be provided side by side downstream, or one roll pair may be provided upstream in the traveling direction of the workpiece and on one side in the width direction of the workpiece, and one roll pair may be provided downstream and on the other side in the width direction of the workpiece. [Explanation of symbols]

[0039] 1 Current collector 2 Cathode active material 3 Negative electrode active material 4,5,6 Roll Pair 4a, 4b, 5a, 5b, 6a, 6b, R roll 7,8,9,10,11,12,13,14,15,16,17,18,B Bearing 19. Cabinet 20, 21, 22 Press Frame 23 Through hole 24, 25, 26, 27, 28, 29, 31 Connecting members 35 recess 36 Sealing material double work

Claims

1. A roll press device that conveys a workpiece while applying a compressive load to the workpiece between a pair of rolls that are provided above and below and are rotatably held at both ends by bearings, The roll pairs are provided in a plurality of positions offset from one another in the width direction of the workpiece. A roll press device characterized by:

2. The roll press device according to claim 1, The roll pairs are arranged with a shift in the travel direction of the workpiece and the width direction of the workpiece, and the roll pair on the upstream side in the travel direction of the workpiece and the roll pair on the downstream side in the travel direction of the workpiece at least partially overlap in the width direction of the workpiece. A roll press device characterized by:

3. The roll press device according to claim 1 or 2, The roll pair includes an upper roll that contacts an upper surface of the workpiece and a lower roll that contacts a lower surface of the workpiece, At least one of the upper roll and the lower roll has an end surface in the axial direction formed with a recess for reducing the rigidity of the end of the one roll. A roll press device characterized by:

4. The roll press device according to claim 3, a bearing that rotatably holds the one roll, At least a portion of the bearing is inserted into the recess. A roll press device characterized by:

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