Cam mechanism

Abstract

This invention provides a cam device that improves the corner shape of the forced return guide portion in order to reduce the overall length of the cam, thereby avoiding contact between the forced return and the forced return guide portion. [Solution] The cam holder 100 is equipped with first and second guide bar support parts at both ends of the first sliding surface, a second sliding surface is formed at the tip of the second support part, and a guide bar 102 is positioned between the two support parts. The cam slider 200 has a projection through which the guide bar passes, a retraction space due to a notch on the second support part side, and first and second sliding surfaces and a third sliding surface that slide with the first and second sliding surfaces of the cam holder. The cam driver 300 drives the slider by contacting the third sliding surface. Furthermore, the cam device is equipped with a return coil spring, and the corner shape of the forced return guide part of the cam driver is chamfered so that the angle between the engaging part and the corner is 25° or more and 35° or less.

Description

Technical Field

[0001] This invention relates to a cam device.

Background Art

[0002] In a press die, with the existing cam shape, it cannot fit inside the die. Therefore, there is a desire to shorten the overall length of the cam, reduce the cam processing space, and also reduce the die weight.

[0003] Patent Document 1 discloses a cam device that can suppress the dimensions in the height direction of the cam device by inserting a spring through a guide bar.

[0004] Patent Document 2 discloses a cam device in which chamfering is performed on the corner of the forced return guide part of the cam driver.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, although the cam device described in Patent Document 1 can make the cam device more compact by suppressing the dimensions in the height direction, there is no suggestion regarding making the overall length of the cam more compact.

[0007] The cam device described in Patent Document 2 illustrates the corner of the forced return guide part, but there is no suggestion regarding avoiding contact between the forced return and the forced return guide part. Also, there is no suggestion regarding the specific dimensions and angles of the engaging part and the corner of the forced return guide part.

[0008] This invention was made to solve the above-mentioned problems, and aims to improve the corner shape of the forced return guide and avoid contact between the forced return and the corner of the forced return guide when the overall length of the cam is made more compact. [Means for solving the problem]

[0009] A cam holder having a first sliding surface for the cam holder, a first support portion for the guide bar provided on one end of the first sliding surface for the cam holder, a second support portion for the guide bar provided on the other end of the first sliding surface for the cam holder, a second sliding surface for the cam holder formed at the tip of the second support portion for the guide bar with a predetermined step difference from the first sliding surface for the cam holder, and a guide bar provided between the first support portion for the guide bar and the second support portion for the guide bar, a projection through which the guide bar passes, a retraction space formed by a notch provided on the second support portion side of the projection, a first sliding surface for the cam slider provided on the upper surface of the projection and sliding with the first sliding surface for the cam holder, and a cam slider A cam device comprising: a cam slider having a cam slider second sliding surface formed with a predetermined step difference from a first sliding surface and sliding with a cam holder second sliding surface, and a cam slider third sliding surface; a cam driver having a cam driver sliding surface that slides with the cam slider third sliding surface and drives the cam slider in a predetermined machining direction; and a coil spring as a return elastic member, wherein when the cam slider is driven, the guide bar second support portion moves forward and backward relative to the retracted space portion, and the corner portion of the forced return guide portion of the cam driver is chamfered such that the angle between the engaging portion and the corner portion is 25° or more and 35° or less.

[0010] A cam device characterized in that, at the corner of the forced return guide portion of the cam driver, if β is the intersection point of the vertical wall portion and the engaging portion, and α is an arbitrary point on the vertical wall portion, the distance H between point α and the intersection point β is 1.0 mm or more and 3.0 mm or less. [Effects of the Invention]

[0011] According to the cam device of this invention, even if vibration occurs in the cam slider due to miniaturization, contact between the forced return plate and the forced return guide can be avoided by improving the shape of the forced return guide. [Brief explanation of the drawing]

[0012] [Figure 1] An exploded perspective view of the cam mechanism of this embodiment. [Figure 2] A diagram of the cam holder according to this embodiment. [Figure 3] A diagram of the cam slider according to this embodiment. [Figure 4] A diagram of the cam driver according to this embodiment. [Figure 5] HH cross-section view in Figure 4. [Figure 6] A diagram showing the movement during processing. [Figure 7] This diagram shows the corners of the conventional forced return guide section with rounded edges. [Figure 8] This diagram shows the corners of the forced return guide section of this embodiment being chamfered to a specific shape. [Modes for carrying out the invention]

[0013] Specific embodiments of this application will be described below with reference to the drawings and examples. Those skilled in the art will be able to clearly and fully understand the technical solution, the technical problem to be solved, and the technical effects to be achieved by this specification. The specific embodiments described herein are for illustrative purposes only and are not intended to be limiting. Furthermore, for the sake of clarity, the drawings show only those relevant to this application.

[0014] Furthermore, the structures, proportions, dimensions, etc., shown in the drawings of the specification are merely supplementary to the description of this specification and intended to assist those skilled in the art in understanding and interpreting it, and are not intended to limit the conditions for implementing this application. Therefore, they do not have any essential technical significance, and any modification of the structure, change in proportions, or adjustment of dimensions is considered to be within the scope of the technical content disclosed in this application, as long as it does not affect the effects and objectives that this application aims to achieve.

[0015] Also, terms such as "first", "second", "the", etc. do not imply a quantitative limitation and can be used for either singular or plural. The terms "comprising", "including", "having" and their derivatives in this application are intended to mean non-exclusive inclusion. That is, a process, method, system, product, or apparatus that includes a certain procedure or module is not limited to the listed procedures or elements, and may further include unlisted procedures or elements, or other procedures or elements inherent to the process, method, product, or apparatus. Furthermore, terms such as "connecting", "coupling", "joining", etc. are not limited to physical or mechanical connections, but also include direct or indirect electrical connections.

[0016] Hereinafter, a cam device according to an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, a hanging cam device will be described, but the form of the cam device is not limited thereto, and for example, a bottom-mounted cam device is also included.

[0017] FIG. 1 is an exploded perspective view of a cam device 1 according to this embodiment. As shown in FIG. 1, the cam device 1 includes a cam holder 100 fixed to an upper die (not shown) of a press die that reciprocates in the press direction, a guide bar 102 suspended and held by the cam holder 100, a cam slider 200 that is inserted through the guide bar 102 and supported slidably, biased in the return direction by a coil spring 205, reciprocates in the processing direction with a predetermined stroke, and a processing tool (not shown) is attached to a processing tool attachment surface 201f, and a cam driver 300 fixed to a fixed die (not shown) and driving the cam slider 200 in a predetermined processing direction.

[0018] FIG. 2 is a perspective view of the cam holder 100 viewed from two directions. The cam holder 100 has a cam holder body 101, a guide bar 102, and a plate 103. The cam holder body 101 has a guide bar first support portion 101a, a guide bar second support portion 101b, a cam holder first sliding surface 101c, a cam holder second sliding surface 101d, and a groove portion 101e.

[0019] The cam holder body 101 is a member made of a metal material, mainly formed of cast iron. The cam holder body 101 is a substantially U-shaped member, and includes a first guide bar support portion 101a integrally formed at the forward end of the cam holder 100 (hereinafter referred to as the front end), a second guide bar support portion 101b formed at the rearward end of the cam holder 100 (hereinafter referred to as the rear end), a guide bar 102 attached to the lower central portion of the cam holder body 101, and a groove portion 101e which is a space for the cam slider 200 to slide.

[0020] The first guide bar support portion 101a has a mounting hole for assembling the guide bar 102. The first guide bar support portion 101a is integral with the cam holder body 101.

[0021] The second guide bar support portion 101b has a mounting hole for assembling the guide bar 102. The second guide bar support portion 101b is integral with the cam holder body 101. The second guide bar support portion 101b may have a second cam holder sliding surface 101d at the lower part. In this case, the second cam holder sliding surface 101d has a step with the first cam holder sliding surface 101c and is formed as a surface parallel to the first cam holder sliding surface 101c. The step in that case is the same as the step between the first cam slider sliding surface 201a and the second cam slider sliding surface 201b described later. A solid lubricant may be embedded in the second cam holder sliding surface 101d.

[0022] In the embodiment, the second cam holder sliding surface 101d is provided, but the second cam holder sliding surface 101d is not an essential component, and a configuration in which only the first cam holder sliding surface 101c and the first cam slider sliding surface 201a receive the load is also possible. However, from the viewpoint of load distribution, it is preferable to provide the second cam holder sliding surface 101d.

[0023] The groove 101e is a groove-shaped portion formed by the lower surface of the cam holder body 101, the side surface of the first guide bar support portion 101a, and the side surface of the second guide bar support portion 101b. The groove 101e has a first sliding surface 101c of the cam holder on its lower surface. That is, the cam holder 100 has a first guide bar support portion 101a on one end of the first sliding surface 101c of the cam holder, and a second guide bar support portion 101b on the other end. The guide bar 102 is fixed between the side surface of the first guide bar support portion 101a and the side surface of the second guide bar support portion 101b within the groove 101e. Within the groove 101e, the projection B of the cam slider 200 fits, and the first sliding surface 101c of the cam holder and the first sliding surface 201a of the cam slider, which will be described later, slide back and forth in contact.

[0024] The guide bar 102 is a metal component. The guide bar 102 is a rod-shaped component with a round, elliptical, or polygonal cross-section. The guide bar 102 is inserted through the guide bar insertion hole 201d, which will be described later, with one end inserted through the mounting hole of the first guide bar support part 101a and the other end inserted through the mounting hole of the second guide bar support part 101b, and fixed with the plate 103. The guide bar 102 guides the movement of the cam slider 200 in the front-rear direction and is a component that suspends the cam slider 200 to prevent it from falling.

[0025] Plate 103 is a component made of metal. Plate 103 has a roughly rectangular shape. Plate 103 is a mounting member for the rear of the guide bar second support portion 101b.

[0026] Figure 3 is a perspective view of the cam slider 200 from two directions. The cam slider 200 includes a cam slider body 201, a guide bush 202, a urethane stopper 203, a forced return plate 204, and a coil spring 205. The cam slider body 201 has a first sliding surface 201a, a second sliding surface 201b, a third sliding surface 201c, a guide bar insertion hole 201d, an elastic body mounting hole 201e, and a machining tool mounting surface 201f.

[0027] The cam slider body 201 is a metal component, mainly made of cast iron. It has a projection B at its upper end, and the projection B has a cam slider first sliding surface 201a on the cam holder side. The cam slider first sliding surface 201a is the surface that slides (sliding contacts) with the cam holder first sliding surface 101c. The projection B of the cam slider body 201 has a guide bar insertion hole 201d that penetrates from the upper front end. The guide bar 102 passes through the guide bar insertion hole 201d. The cam slider body 201 has an elastic body mounting hole 201e below the guide bar insertion hole 201d. A coil spring 205 is assembled into the elastic body mounting hole 201e.

[0028] The cam slider body 201 has a first sliding surface 201a and a second sliding surface 201b which is formed at a step above the first sliding surface 201a and is parallel to the first sliding surface 201a.

[0029] The cam slider 200 has a retraction space A formed by a notch (the space above the second sliding surface 201b of the cam slider) provided on the guide bar second support portion 101b side of the upper projection B. The retraction space A is a notch provided on the upper part of the cam slider body 201. When the cam device 1 is in operation (when the cam slider 200 moves forward), the guide bar second support portion 101b in the retraction space A moves relatively backward (away from projection B). When the cam slider 200 moves backward, the guide bar second support portion 101b in the retraction space A moves relatively forward (closer to projection B). In this way, when the cam slider 200 is driven, the guide bar second support portion 101b moves relatively back and forth within the retraction space A (approaching and moving away from projection B). When the cam holder second sliding surface 101d and the cam slider second sliding surface 201b are in sliding contact, the cam holder second sliding surface 101d moves back and forth in the retraction space A and comes into contact with the cam slider second sliding surface 201b.

[0030] The guide bush 202 is a metal component, mainly made of a copper alloy. The guide bush 202 is a cylindrical component. The guide bush 202 is assembled into the guide bar insertion hole 201d. The guide bush 202 slides against the guide bar 102 and is a component that prevents seizing.

[0031] The coil spring 205 is a component made of metal. The coil spring 205 has a helical shape. The coil spring 205 elastically deforms in response to the load, generating a restoring force, and is used as a return elastic member to allow the cam slider 200 to return to its original position after machining the workpiece.

[0032] The return elastic member contacts the inner wall of the cam holder body 101 at the corresponding position. The return elastic member is a coil spring 205. When the cam holder 100 rises, the cam slider 200 returns to its initial position due to the repulsive force of the return elastic member.

[0033] The urethane stopper 203 is a component made of urethane. The urethane stopper 203 is assembled to the rear of the cam slider body 201. The urethane stopper 203 mitigates the impact force when the cam slider 200 returns to its initial position and comes into contact with the cam holder 100.

[0034] The cam slider body 201 has a forced return plate 204 on one or both sides. The forced return plate 204 is a component made of metal. The forced return plate 204 has a roughly rectangular shape. The forced return plate 204 is a component that physically returns the cam slider 200 when the tool gets stuck to the panel and the cam slider 200 does not return when the cam device 1 is in operation.

[0035] Figure 4 is a side view of the cam driver 300. The cam driver 300 has a cam driver body 301. The cam driver body 301 is a metal component, mainly made of cast iron. The cam driver body 301 has a cam driver sliding surface 301a on its upper surface. The cam driver sliding surface 301a slides (sliding in contact with) the cam slider third sliding surface 201c. The cam driver 300 is a component that guides the cam slider 200 in the machining direction.

[0036] The cam driver 300 is equipped with a guide portion consisting of a gripping portion 301b and a K-corner portion 301c on one or both sides of its side surface. The gripping portion 301b is the point that contacts the forced return plate 204 and delivers an impact to the cam slider 200 when the tool bites into the panel during operation of the cam device 1 and the cam slider 200 does not return. The K-corner portion 301c is a chamfered shape with a specific angle and dimensions, and the K-corner portion 301c is a continuous surface with the gripping portion 301b.

[0037] Figure 5 is a cross-sectional view taken along line H-H in Figure 4. The cam driver sliding surface 301a is located on the upper surface of the cam driver 300, and the engaging portion 301b is provided between the bottom surface of the cam driver 300 and the cam driver sliding surface 301a, forming a stepped shape.

[0038] Figure 6 shows the movement of the cam device 1 in this embodiment during machining. Figure 6(a) shows the state of the cam device 1 when the upper die is at the top dead center position (cam slider retracted position, hereinafter simply referred to as the retracted position), and Figure 6(b) shows the state of the cam device 1 when the upper die is at the bottom dead center position (cam slider advanced position, hereinafter simply referred to as the advanced position).

[0039] During the operation of the cam device 1, the cam holder 100 and the cam slider 200 move downward together with the upper die (not shown) of the mold. The third sliding surface 201c of the cam slider 200, located at the bottom of the cam slider 200, comes into contact with the cam driver sliding surface 301a, located at the top of the cam driver 300. Subsequently, the cam slider 200 moves along the cam driver sliding surface 301a in the machining direction (from the retracted position to the forward position). Further downward movement of the upper die causes the machining tool (not shown) attached to the tool mounting surface 201f of the cam slider 200 to move in the machining direction (from the retracted position to the forward position) to perform drilling or bending operations on the workpiece (not shown) placed in the mold (position shown in Figure 6(b)).

[0040] As shown in Figure 6, when drilling or bending a workpiece, the second guide bar support portion 101b moves relatively back and forth within the retraction space portion A provided above the cam slider 200 (that is, although the second guide bar support portion 101b actually only moves up and down, when viewed from the retraction space portion A, the second guide bar support portion 101b moves back and forth within the retraction space portion A provided above the cam slider 200). By providing a retraction space portion A that allows the second guide bar support portion 101b to move forward and backward, the overall length of the cam holder 100, and consequently the cam device 1, can be reduced. The overall length of the cam device 1 is the length in the front-rear direction of the cam device 1 when the direction in which the cam slider 200 moves to process the workpiece by the cam driver sliding surface 301a is defined as the forward direction.

[0041] After machining, the cam slider 200 moves along the sliding surface (from the forward position to the retracted position) as the upper die moves upward, and returns to its original retracted position before machining as the upper die moves further (position shown in Figure 6(a)).

[0042] As described above, by providing the cam slider 200 with a retraction space A formed by a notch on the guide bar second support side of the projection B, the guide bar second support 101b moves back and forth in the retraction space A provided on the upper part of the cam slider 200, thereby reducing the length of the cam holder 100 and making it more compact.

[0043] In compact cam mechanisms, when the cam slider contacts the cam driver during press working, this contact causes an impact on the cam slider, resulting in vibration. In conventional cam mechanisms, after the vibration of the cam slider subsides, the cam slider moves in the machining direction along the sliding surface of the cam driver. Therefore, contact between the forced return plate and the forced return guide portion of the cam driver can be avoided even if the corners of the guide portion are rounded. In contrast, with a compact cam mechanism, the cam slider moves in the machining direction before the vibration of the cam slider subsides, which may cause the lower part of the forced return plate to come into contact with the rounded chamfer formed on the corner of the forced return guide of the cam driver.

[0044] This invention aims to prevent damage to the corners of the forced return guide section of the cam driver even when such a phenomenon occurs, by improving the shape of the corners. Figure 7 shows a conventional corner with a rounded chamfer shape, and Figure 8 shows a corner with a specific shape according to this invention.

[0045] Figure 7 shows a conventional cam driver configuration different from that of Patent Document 2. This figure shows the M-shaped corner 301e formed on the guide portion of the cam device with an R-chamfer. The M-shaped corner 301e is positioned so as not to contact the coil spring 205 and the forced return plate 204 during normal operation. However, if vibration occurs in the cam slider 200 during press working, the forced return plate 204 may be displaced beyond its normal operating range due to this vibration. In such a case, if the vibration amplitude of the lower part of the forced return plate 204 exceeds the range that can avoid contact with the M-shaped corner 301e, the lower part of the forced return plate 204 may come into contact with the R-chamfered M-shaped corner 301e. This contact may hinder the operation of the forced return plate 204 or cause wear or damage to the contact area.

[0046] Figure 8 shows a guide portion applied to the cam device 1 of this embodiment, in which the K-corner portion 301c is chamfered with a shape that specifies the angle and distance range. Even if vibration occurs in the cam slider 200 during press working, it is possible to suppress the lower part of the forced return plate 204 from contacting the K-corner portion 301c. The angle formed by the engagement portion 301b and the K-corner portion 301c is denoted as θ1. The K-corner portion 301c and the vertical wall portion 301d are composed of a continuous surface. If the intersection point of the vertical wall portion 301d and the engagement portion 301b is denoted as β, and any point on the vertical wall portion 301d is denoted as α, then the distance between point α and the intersection point β is denoted as H. The distance L is determined based on the distance H and θ1. [Examples]

[0047] Table 1 shows an example of the corner portion of the cam driver forced return guide.

[0048] Examples 1 to 5 are based on the present invention and feature chamfers on the corners with a distance H of 1.0 mm to 3.0 mm and a θ1 of 25°.

[0049] Examples 6 to 10 are based on the present invention and feature chamfers on the corners with a distance H of 1.0 mm to 3.0 mm and a θ1 of 30°.

[0050] Examples 11 to 15 are based on the present invention and feature chamfers on the corners with a distance H of 1.0 mm to 3.0 mm and a θ1 of 35°.

[0051] Comparative Example 1 had a 1.0 mm radius R-chamfer applied to the corners, while Comparative Example 2 had a C-chamfer with θ1 at 45°. These were assembled into a press machine and a punching test was conducted.

[0052] As a result, comparative examples 1 and 2, which were subjected to conventional processing on the corners of the forced return guide section, showed damage to the corners. However, examples 1 to 15, which were subjected to the processing of the present invention, showed no abnormalities on the corners of the forced return guide section, indicating that damage was avoided.

[0053] [Table 1] [Industrial applicability]

[0054] The cam mechanism according to this invention can be applied to press molding dies in various industrial fields, not just the automotive sector, and can be used as a die unit for processing metal sheet materials. [Explanation of Symbols]

[0055] 1: Cam mechanism 100: Cam holder 101: Cam holder body 101a: Guide bar first support part 101b: Guide bar second support part 101c: Cam holder first sliding surface 101d: Cam holder second sliding surface 101e: Groove 102: Guide bar 103: Plate 200: Cam slider 201: Cam slider body 201a: Cam slider first sliding surface 201b: Cam slider second sliding surface 201c: Cam slider third sliding surface 201d: Guide bar insertion hole 201e: Elastic body mounting hole 201f: Mounting surface for machining tools 202: Guide bush 203: Urethane stopper 204: Force return plate 205: Coil spring 300: Cam Driver 301: Cam driver body 301a: Cam driver sliding surface 301b: Hanging part 301c:K corner 301d: Vertical Wall Section 301e:M corner θ1: Chamfer angle

Claims

1. A cam holder first sliding surface, a guide bar first support portion provided on one end of the cam holder first sliding surface, a guide bar second support portion provided on the other end of the cam holder first sliding surface, and a cam holder second sliding surface formed at the tip of the guide bar second support portion with a predetermined step difference from the cam holder first sliding surface, A cam holder having a guide bar provided between the first guide bar support portion and the second guide bar support portion, A cam slider having a projection through which the guide bar passes, a retraction space formed by a notch provided on the guide bar second support side of the projection, a first sliding surface of the cam slider provided on the upper surface of the projection and sliding with the first sliding surface of the cam holder, a second sliding surface of the cam slider formed with a predetermined step difference from the first sliding surface of the cam slider and sliding with the second sliding surface of the cam holder, and a third sliding surface of the cam slider, A cam driver having a cam driver sliding surface that slides with the third sliding surface of the cam slider and drives the cam slider in a predetermined machining direction, A coil spring as a return elastic member, A cam device comprising, When the cam slider is driven, the second support portion of the guide bar moves forward and backward relative to the retracted space. The corner of the forced return guide portion of the cam driver is chamfered so that the angle between the engaging portion and the corner is 25° or more and 35° or less. A cam mechanism characterized by the following.

2. The cam device according to claim 1, characterized in that, at the corner of the forced return guide portion of the cam driver, if β is the intersection of the vertical wall portion and the engaging portion, and α is an arbitrary point on the vertical wall portion, the distance between α and β is 1.0 mm or more and 3.0 mm or less.

Images