Cam mechanism

Abstract

To provide a cam device that can shorten the overall length of the cam. [Solution] A cam device comprising: a cam holder having a first sliding surface of the cam holder; a first support portion for a guide bar provided on one end of the first sliding surface of the cam holder; a second support portion for a guide bar provided on the other end of the first sliding surface of the cam holder; and a guide bar provided between the first support portion for the guide bar and the second support portion of the guide bar; a cam slider having a projection through which the guide bar passes; a retraction space formed by a notch provided on the side of the projection that is the second support portion of the guide bar; a first sliding surface for a cam slider and a third sliding surface for a cam slider provided on the upper surface of the projection that slides with the first sliding surface of the cam holder; and a cam driver having a sliding surface for a cam driver that slides with the third sliding surface of the cam slider and drives the cam slider in a predetermined machining direction, wherein when the cam slider is driven, the second support portion for the guide bar moves relatively back and forth within the retraction space.

Description

Technical Field

[0001] The present invention relates to a cam device.

Background Art

[0002] In a press die, with the existing cam shape, it cannot fit within the die. Thus, there is a desire to shorten the total length of the cam, keep the cam machining space small, and also keep the die weight low.

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

Prior Art Documents

Patent Documents

[0004] <000002A>

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the cam device described in Patent Document 1 can make the cam device more compact by suppressing the height direction, but there is no suggestion regarding making the total length of the cam more compact.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a cam device capable of shortening the total length of the cam.

Means for Solving the Problems

[0007] The present invention relates to a cam holder having a first sliding surface of the cam holder, a first support portion for a guide bar provided on one end of the first sliding surface of the cam holder, a second support portion for a guide bar provided on the other end of the first sliding surface of the cam holder, and a guide bar provided between the first support portion and the second support portion of the guide bar, a projection through which the guide bar passes, a retraction space formed by a notch provided on the side of the projection that faces the second support portion of the guide bar, a first sliding surface for a cam slider provided on the upper surface of the projection and sliding with the first sliding surface of the cam holder, and a third sliding surface for a cam slider A cam device comprising a cam slider having a moving surface and 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, wherein one end of the first sliding surface of the cam holder is the forward direction side in which the cam slider is driven in a predetermined machining direction, and the other end of the first sliding surface of the cam holder is the backward direction side in which the cam slider returns in the opposite direction to the predetermined machining direction, and the second support part of the guide bar moves relatively back and forth within the retraction space when the cam slider is driven.

Effects of the Invention

[0008] According to the cam device of the present invention, the total length of the cam can be shortened.

Brief Description of the Drawings

[0009] [Figure 1] This is an exploded perspective view of the cam device of this embodiment. [Figure 2] This is a diagram of the cam holder according to this embodiment. [Figure 3] This is a diagram of the cam slider according to this embodiment. [Figure 4] This diagram shows the movement of the cam device of this embodiment during machining. [Figure 5] This figure shows the overall length of a conventional cam device and the device of this embodiment. [Figure 6] This diagram shows the forces acting on the cam mechanism of this embodiment. [Figure 7] This figure shows the angle of the cam driver sliding surface in this embodiment. [Figure 8] This figure shows the sliding area in the cam device of this embodiment. [Modes for carrying out the invention]

[0010] The following describes in detail an embodiment of the present invention, specifically a cam device, with reference to the figures. While this embodiment describes a suspended cam device, the type of cam device is not limited to this, and includes, for example, a bottom-mounted cam device.

[0011] Figure 1 is an exploded perspective view of the cam device 1 of this embodiment. As shown in Figure 1, the cam device 1 includes a cam holder 100 fixed to a moving die (not shown) of a press die that reciprocates in the pressing direction (direction P in Figure 6), a guide bar 102 suspended and held by the cam holder 100, a cam slider 200 through which the guide bar 102 is inserted and slidably supported, biased in the return direction by a gas spring 205 or a coil spring 206, which reciprocates in the machining direction (direction F in Figure 6) with a predetermined stroke, and a machining tool (not shown) attached to the machining tool mounting surface 201f, and a cam driver 300 fixed to a fixed die (not shown) that drives the cam slider 200 in a predetermined machining direction.

[0012] Figure 2 is a perspective view of the cam holder 100 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 first guide bar support portion 101a, a second guide bar support portion 101b, a first cam holder sliding surface 101c, a second cam holder sliding surface 101d, and a groove portion 101e.

[0013] The cam holder body 101 is a metal component, mainly made of cast iron. The cam holder body 101 is a substantially U-shaped component and has a first guide bar support portion 101a integrally formed at the forward end (hereinafter referred to as the front end) of the cam holder 100, a second guide bar support portion 101b formed at the backward end (hereinafter referred to as the rear end) of the cam holder 100, a guide bar 102 attached to the lower central part of the cam holder body 101, and a groove portion 101e which is a space for the cam slider 200 to slide.

[0014] 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 integrated with the cam holder body 101.

[0015] 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 integrated with the cam holder body 101. The second guide bar support portion 101b may also have a second cam holder sliding surface 101d at its lower part. In this case, the second cam holder sliding surface 101d has a step difference with the first cam holder sliding surface 101c and is formed as a surface parallel to the first cam holder sliding surface 101c, and the step difference in this case is the same as the step difference between the first cam slider sliding surface 201a and the second cam slider sliding surface 201b, which will be described later. A solid lubricant may be embedded in the second cam holder sliding surface 101d.

[0016] In the embodiment, the second sliding surface 101d of the cam holder is provided. However, the second sliding surface 101d of the cam holder is not an essential component, and a configuration in which only the first sliding surface 101c of the cam holder and the first sliding surface 201a of the cam slider receive the load is also possible. However, from the viewpoint of load distribution, it is preferable to provide the second sliding surface 101d of the cam holder.

[0017] The groove portion 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 portion 101e has the first sliding surface 101c of the cam holder on the lower surface portion. That is, the cam holder 100 includes the first guide bar support portion 101a on one end side of the first sliding surface 101c of the cam holder and the second guide bar support portion 101b on the other end side. A 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 10a in the groove portion 101e. In the groove portion 101e, the protrusion B of the cam slider 200 is fitted, and the first sliding surface 101c of the cam holder and the first sliding surface 201a of the cam slider described later slide in contact with each other back and forth.

[0018] The guide bar 102 is a member made of a metal material. The guide bar 102 is a rod-shaped member having a circular, elliptical, or polygonal cross-sectional shape. The guide bar 102 is inserted into a guide bar insertion hole 201d described later, one end is inserted into the mounting hole of the first guide bar support portion 101a, and the other end is inserted into the mounting hole of the second guide bar support portion 102b and fixed by a plate 103. The guide bar 102 guides the forward and backward movement of the cam slider 200 and is a member that suspends the cam slider 200 so that it does not fall.

[0019] The plate 103 is a member made of a metal material. The plate 103 has a substantially rectangular shape. The plate 103 is a mounting member for the rear portion of the second guide bar support portion 101b.

[0020] 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 gas spring 205 or a coil spring 206. 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.

[0021] 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 cam slider first sliding surface 201a is on the cam holder side of projection B. The cam slider first sliding surface 201a is the surface that slides (sliding contact) 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. Below the guide bar insertion hole 201d, the cam slider body 201 has an elastic body mounting hole 201e. A gas spring 205, a coil spring 206, or a urethane spring (not shown) is assembled into the elastic body mounting hole 201e.

[0022] The cam slider body 201 is formed at a position with a step difference from the cam slider first sliding surface 201a and has a cam slider second sliding surface 201b that is parallel to the cam slider first sliding surface 201a.

[0023] 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.

[0024] 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.

[0025] The gas spring 205 is a component made of metal. The gas spring 205 comprises a cylindrical cylinder body and a piston rod extending axially from one end thereof. The gas spring 205 is used as a return elastic member to allow the cam slider 200 to return to its original position after machining the workpiece, using high-pressure gas (e.g., nitrogen) sealed inside the cylinder body. The coil spring 206 is a component made of metal. The coil spring 206 has a helical shape. The coil spring 206 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.

[0026] The return elastic member contacts the inner wall of the cam holder body 101 at the corresponding position. Depending on the operation of the cam device 1, the return elastic member can be selected as either a gas spring 205 or a coil spring 206. 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.

[0027] 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.

[0028] 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.

[0029] The cam driver 300 has a cam driver body 301. The cam driver body 301 is a component made of metal, mainly 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 (slids 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.

[0030] Figure 4 shows the movement of the cam device 1 of this embodiment during machining. Figure 4(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 4(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).

[0031] 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 4(b)).

[0032] As shown in Figure 4, when drilling or bending a workpiece, the second guide bar support 101b moves relatively back and forth within the retraction space A provided above the cam slider 200 (that is, although the second guide bar support 101b actually only moves up and down, when viewed from the retraction space A, the second guide bar support 101b moves back and forth within the retraction space A provided above the cam slider 200). By providing a retraction space A that allows the second guide bar support 101b to move forward and backward, the overall length of the cam holder 100, and consequently the cam device 1 (l1 in Figure 5(b)), can be reduced. The overall length of the cam device 1 is the length in the front-to-back 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 301 is defined as the forward direction.

[0033] 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 4(a)).

[0034] 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.

[0035] Figure 5 shows the total length of a conventional cam device and the cam device of this embodiment. In Figure 5(a), the total length of the conventional cam device is shown as l0, and in Figure 5(b), the total length of the cam device 1 of this embodiment is shown as l1. Because the cam device 1 of this embodiment has a structure in which the guide bar second support portion 101b can move in and out of the retraction space A, it is possible to shorten the total length compared to a conventional cam device that does not have a retraction space.

[0036] Table 1 compares the overall lengths of the cam device 1 of the embodiment and the conventional cam device when the machining force is the same (15.0 kN). The cam device 1 of the embodiment was able to reduce the overall length by 32% compared to the conventional cam device.

[0037] [Table 1]

[0038] In addition, the cam device 1 may receive the main load on the first sliding surface 201a of the cam slider (first sliding surface 101c of the cam holder), and supplementarily receive it on the second sliding surface 101d of the cam holder (second sliding surface 201b of the cam slider), with the second sliding surface 101d of the cam holder and the second sliding surface 201b of the cam slider sliding in sliding contact.

[0039] Figure 6 shows the forces acting on the cam device 1 of the embodiment. The machining angle θ1 in the figure is the angle that the cam driver sliding surface 301a makes with the horizontal plane (a plane perpendicular to the operating direction of the press die; the same applies hereinafter), and the cam angle θ2 in the figure is the angle that the cam holder first sliding surface 101c makes with the horizontal plane. The machining force F in the figure is the force generated when the cam slider 200 moves forward and protrudes due to the descent of the upper die, and when the piercing (not shown) attached to the tip punches out the steel plate.

[0040] In the figure, the press force P is the force applied to the cam device 1 by the descent of the upper die. The component force V in the figure is the vertical component force acting between the third sliding surface 201c of the cam slider and the sliding surface 301a of the cam driver due to the processing force F. The component force Q1 in the figure is the vertical component force acting between the first sliding surface 201a of the cam slider and the first sliding surface 101c of the cam holder due to the processing force F. The component force Q2 in the figure is the vertical component force acting between the second sliding surface 201b of the cam slider and the second sliding surface 101d of the cam holder. In the figure, S is the extrusion stroke of the cam slider 200 in the processing direction. In the figure, S' is the spring stroke of the cam slider 200 relative to the cam holder 100, and is the width returned by a gas spring or spring (not shown). In the figure, L is the press stroke of the upper die (not shown) from top dead center to bottom dead center.

[0041] Figure 6 shows the state where the upper die (not shown) has descended by L in the vertical direction (press direction) from the top dead center, and the cam slider 200 has moved by S in the machining direction. At this time, a force P is applied to the cam holder 100 due to the descent of the upper die (not shown). The cam holder 100 pushes the cam slider 200 with a force Q1 in a direction perpendicular to the first sliding surface 101c of the cam holder (first sliding surface 201a of the cam slider). The cam holder 100 pushes the cam slider 200 with a force Q2 in a direction perpendicular to the second sliding surface 201b of the cam slider (second sliding surface 101d of the cam holder). A force V is applied to the cam driver 300 in a direction perpendicular to the sliding surface 301a of the cam driver (third sliding surface 201c of the cam slider). A force F pushes out a tool such as a piercing (not shown) in a direction parallel to the cam driver sliding surface 301a (cam slider third sliding surface 201c).

[0042] Furthermore, the relationship between these forces is defined as follows. The relationship between the pressing force P and the processing force F is: P = F·(cosθ² / sin(θ1+θ²)) The component force acting on the first sliding surface 201a of the cam slider (first sliding surface 101c of the cam holder) and the second sliding surface 201b of the cam slider (second sliding surface 101d of the cam holder) (hereinafter referred to as the cam holder side component force) (Q1 + Q2) is, (Q1+Q2)=F·(1 / sin(θ1+θ2)) The component force V acting on the cam driver sliding surface 301a (cam slider third sliding surface 201c) (hereinafter referred to as the cam driver side component force) is: V = F·(1 / tan(θ1+θ2)) This is shown.

[0043] In this embodiment, by setting a predetermined relationship between the cam holder side component force (Q1 + Q2) and the cam driver side component force V of the machining force F, wear on the cam driver sliding surface 301a can be reduced, and for example, when a piercing is attached as a tool, the misalignment of the piercing axis can be reduced.

[0044] Holm's wear formula is generally known for material wear. The amount of wear (W) of a sliding material is given by the following formula: W=Z(P·L / P H ) This formula shows that the amount of wear (W) is proportional to the coefficient of wear Z, the load P, and the friction distance L, and the hardness P H This shows that it is inversely proportional. It also shows that load P and wear are proportional.

[0045] From Holm's wear formula, it can be seen that in order to minimize wear, the load P needs to be reduced. When the contact area between the first sliding surface 201a of the cam slider and the first sliding surface 101c of the cam holder is Sh1, the contact area between the second sliding surface 201b of the cam slider and the second sliding surface 101d of the cam holder is Sh2, the contact area between the third sliding surface 201c of the cam slider and the sliding surface 301a of the cam driver is Sh3, the graphite embedding rate in the sliding area Sh1 of the first sliding surface 201a of the cam slider and the sliding area Sh2 of the second sliding surface 201b of the cam slider is Gh(%), and the graphite embedding rate in the sliding area Sh3 of the third sliding surface 201c of the cam slider is Gd(%), the surface pressure generated on the first sliding surface 201a of the cam slider and the second sliding surface 201b of the cam slider is ((Q1+Q2) / ((Sh1+ The cam holder-cam driver surface pressure ratio, which is the ratio of the surface pressure (V / (Sh3·cosθ3 (1-Gd / 100))) generated on the cam driver sliding surface 301a to Sh2)·(1-Gh / 100)), is preferably as follows. 1.0≦((Q1+Q2) / (Sh1+Sh2)·(1-Gh / 100))) / (V / (Sh3·cosθ3(1-Gd / 100)))≦2.0

[0046] Figure 7 is a view of the cam mechanism 1 in Figure 6 as seen from arrow Y. When a virtual surface 301b is formed at an angle θ1 from the bottom surface of the cam driver 300, the angle formed by the two surfaces, the virtual surface 301b and the cam driver sliding surface 301a, is defined as the cam driver inclination angle θ3. The cam driver sliding surface 301a is roof-shaped with an inclination of θ3 relative to the horizontal plane to prevent runout, and generally the cam driver inclination angle θ3 is 30°.

[0047] Figure 8 shows the sliding surface area. Figure 8(a) shows the sliding surface area Sh1 of the first sliding surface 201a of the cam slider, the sliding surface area Sh2 of the second sliding surface 201b of the cam slider, the chamfered area 201g, and the solid lubricant embedded area 201h. Figure 8(b) shows the sliding surface area Sh3 of the third sliding surface 201c of the cam slider, the chamfered area 201g, and the solid lubricant embedded area 201h.

[0048] Here, the sliding area Sh1 is the actual sliding area where the first sliding surface 201a of the cam slider and the first sliding surface 101c of the cam holder come into contact. The sliding area Sh2 is the actual sliding area where the second sliding surface 201b of the cam slider and the second sliding surface 101d of the cam holder come into contact. The sliding area Sh3 is the actual sliding area where the third sliding surface 201c of the cam slider and the sliding surface 301a of the cam driver come into contact.

[0049] The area remaining after subtracting the solid lubricant embedded area 201h from the sliding surface areas Sh1, Sh2, and Sh3 is the base material area, and surface pressure is applied to this base material area.

[0050] Table 2 shows the examples and comparative examples. Examples 1, 2, and 3 show the cases where the processing force is 15kN, 20kN, and 25kN. Similarly, comparative examples 1, 2, and 3 also show the cases where the processing force is 15kN, 20kN, and 25kN. The cam holder side component force Q(Q1+Q2) and the cam driver side component force V generated at that time are given by equations (1) and (3). In these examples and comparative examples, (θ1+θ2)=50° was used for calculation. The base material area is the sliding part area excluding the solid lubricant embedded portion, and in the case of an inclined surface, it represents the actual area bearing the load projected onto the horizontal area. In Table 2, CH side refers to the cam holder side, and CD side refers to the cam driver side.

[0051] Maintaining a cam holder / cam slider surface pressure ratio of 1 or more indicates a reduction in overall length. For example, if the overall length is increased by connecting two cam holders and cam sliders, contrary to the present invention, the surface pressure ratio becomes 1 / 2. The relationship between Example 1 and Comparative Example 1 illustrates this. That is, if the sliding surface area on the cam holder side is doubled, the surface pressure becomes 1 / 2, and the cam holder / cam slider surface pressure ratio becomes 1 / 2. The relationship between Example 1 and Comparative Example 1 illustrates this. In this case, the wear amount on the cam holder side sliding surface is 11.4 μm, and the wear amount on the cam driver side sliding surface is 13.1 μm. As a result, wear progresses on the cam driver side sliding surface, which serves as the reference surface, and the rotation accuracy of the cam decreases.

[0052] Comparative Example 2 also shows an example where the surface pressure ratio is 1 or less. When the surface pressure ratio is less than 1, the surface pressure on the cam driver side sliding surface increases relatively, leading to greater wear on the cam driver side, which is the reference surface, and significant runout of the shaft. Furthermore, as in Comparative Example 3, when the surface pressure ratio exceeds 2.0, excessive surface pressure is generated on the cam holder side, resulting in severe wear on the cam holder side. Thus, it can be seen that a surface pressure ratio between 1.0 and 2.0 is within the range that prevents wear on the cam driver surface, which is the reference surface, and maintains stable sliding.

[0053] [Table 2]

[0054] As described above, the cam device of this embodiment allows for a reduced overall length of the cam device, thereby reducing the mold weight and shortening the overall length to avoid rearward ejection and rearward interference. Furthermore, it is possible to provide a cam device that controls wear through pressure distribution and reduces misalignment of the piercing pins. [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 section 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 201g: Chamfered area 201h: Location where solid lubricant is embedded 202: Guide bush 203: Urethane stopper 204: Force return plate 205: Gas spring 206: Coil spring 300: Cam Driver 301: Cam driver body 301a: Cam driver sliding surface 301b: Virtual surface A: Evacuation space B:Protrusion θ1: Machining angle θ2: Cam angle θ3: Cam driver tilt angle

Claims

1. Cam holder first sliding surface and A first guide bar support portion provided on one end of the first sliding surface of the cam holder, The second support portion of the guide bar is provided on the other end side of the first sliding surface of the cam holder, A guide bar provided between the first guide bar support and the second guide bar support, A cam holder having, The projection through which the guide bar passes, The retraction space is formed by the notch provided on the second support portion side of the projection, A cam slider first sliding surface is provided on the upper surface of the projection and slides with the cam holder first sliding surface, Cam slider third sliding surface and A cam slider having, 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 cam device having, The one end of the first sliding surface of the cam holder is the forward direction side in which the cam slider is driven in the predetermined machining direction. The other end of the first sliding surface of the cam holder is the side in the retraction direction when the cam slider returns in the opposite direction to the predetermined machining direction. A cam device in which, when the cam slider is driven, the second support portion of the guide bar moves forward and backward relative to the retracted space.

2. The cam device according to claim 1, wherein the cross-sectional shape of the guide bar is one of the shapes of a circle, an ellipse, or a polygon.

3. The aforementioned cam holder is, The tip of the second support portion of the guide bar has a second sliding surface for the cam holder, which is formed with a predetermined step difference from the first sliding surface for the cam holder. The aforementioned cam slider is, The cam device according to claim 1, further comprising a cam slider second sliding surface formed with a predetermined step difference from the cam slider first sliding surface and sliding with the cam holder second sliding surface.

4. Let Q1 be the force applied between the first sliding surface of the cam slider and the first sliding surface of the cam holder, and let Q2 be the force applied between the second sliding surface of the cam slider and the second sliding surface of the cam holder. Let V be the force applied between the cam driver sliding surface and the third sliding surface of the cam slider. Let Sh1 be the sliding surface area between the first sliding surface of the cam slider and the first sliding surface of the cam holder. Let Sh2 be the sliding surface area between the second sliding surface of the cam slider and the second sliding surface of the cam holder. Let Sh3 be the sliding surface area between the cam driver sliding surface and the third sliding surface of the cam slider. Let Gh(%) be the graphite embedding rate of the first sliding surface of the cam slider and the second sliding surface of the cam slider. Let Gd (%) be the graphite embedding rate of the third sliding surface of the cam slider. When the inclination angle of the cam driver on the cam driver sliding surface is θ3, The cam device according to claim 3, wherein the ratio of the surface pressure (V / (Sh3・cosθ3 (1-Gd / 100))) to the surface pressure ((Q1+Q2) / ((Sh1+Sh2)・(1-Gh / 100))) is given by the following formula. 1.0≦((Q1+Q2) / ((Sh1+ Sh2)・(1-Gh / 100))) / (V / Sh3・cosθ3 (1-Gd / 100)) ≦2.0

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