Vehicle latch device and method for manufacturing the same

Abstract

The present invention provides a vehicle latch device that strengthens the attachment of the cushioning part to the engaging pawl of the ratchet, thereby enabling the engaging pawl and cushioning part to withstand long-term use, and that can reduce the contact noise when the latch and ratchet come into contact with each other over a long period of time. [Solution] In a vehicle latch device, a groove is formed in at least a part of the engaging claw portion of the metal ratchet body of the ratchet, along the rotational direction of the ratchet, and a synthetic resin molded part is integrally molded into the ratchet, covering a part of the engaging claw portion with synthetic resin so that the metal surface of the ratchet body is exposed, and the synthetic resin molded part covers the groove portion and has a cushioning portion that protrudes more than the exposed metal surface of the engaging claw portion and can contact the engaging portion of the latch, and the ratchet has an uneven surface formed on at least the surface of the groove portion.

Description

Technical Field

[0001] The present invention relates to a latch device for vehicle doors, back doors, and the like, and a manufacturing method thereof, and particularly to a door latch device having a frictional force reduction structure and a manufacturing method thereof.

Background Art

[0002] As a conventional vehicle latch device, for example, there is one disclosed in Patent Document 1. That is, as in the invention of Patent Document 1, a structure is known in which a groove portion is provided at the central portion in the plate thickness direction of an engaging claw portion provided on a metal ratchet, and resin is fitted into the groove portion to form a buffer portion. In this structure, the buffer portion made of resin slightly protrudes beyond the exposed metal surface of the engaging claw portion, and the buffer portion of the engaging claw portion is connected to the sliding surface where the latch and the ratchet slide. Therefore, when the latch rotates in the full closing direction, the latch and the ratchet slide smoothly, and when the latch returns from the overstroke position to the full latch position, the latch abuts against the buffer portion, thereby suppressing the generation of abnormal noise.

[0003] Further, Patent Document 2 and Patent Document 3 disclose structures in which a plurality of holding recesses are provided on the engaging surfaces of the first engaging portion and the second engaging portion of a latch by shot peening or the like. Since the lubricant can be held over a wide range of the first engaging portion and the second engaging portion, the lubricant can be uniformly supplied over the wide range of the first engaging portion and the second engaging portion, and it is described that the operability of the vehicle door lock device can be further improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

[0005] However, while the structure of the invention described in Patent Document 1 is highly effective in suppressing the generation of abnormal noise when the latch and ratchet come into contact, there are still challenges in ensuring that the latch slides smoothly when moving from the fully closed position to the open position. There is room for improvement in terms of improving operability by reducing the operating force required when releasing the latch. Furthermore, in the structure of this invention, when the full latch engagement portion of the latch engages with the ratchet in the full latch position, stress concentrates at the lower end of the resin stress buffer portion, that is, at the portion in contact with the stepped portion of the groove (see Figures 13A and 13B). In particular, in latch devices for vehicles intended for long-term use, it is necessary to have fatigue strength that can withstand fatigue failure of the resin due to repeated opening and closing of the door. As a measure to improve this fatigue strength, the invention of Patent Document 1 improves durability by making the buffer portion thicker by making the groove portion deeper when put into practical use. However, there is a problem in that it is difficult to process a narrow and deep groove portion due to the constraints on the width in the plate thickness direction of the ratchet. That is, the metal body portion of the ratchet is formed by punching out a steel plate, for example, and then cutting it to form the groove portion. Therefore, the deeper the groove portion, the deeper the cutting depth, which has adverse effects on processing accuracy, processing time, and load on the tool.

[0006] Patent documents 2 and 3 describe improvements to the operability of a ratchet that engages with a shot-peened latch, but there is a problem in that sufficient consideration has not been given to the noise that occurs when the latch and ratchet come into contact.

[0007] In view of the above-mentioned problems, the present invention aims to provide a vehicle latch device that strengthens the fixation of the cushioning part to the engaging pawl of the ratchet, thereby enabling the engaging pawl and cushioning part to withstand long-term use, reducing the operating force of the ratchet during latch release operations, and also mitigating the contact noise when the latch and ratchet come into contact with each other over a long period of time. Another object of the present invention is to provide a vehicle latch device that eliminates the need to deepen the groove to mitigate the cushioning force experienced by the cushioning portion when the latch and ratchet come into contact with each other. [Means for solving the problem]

[0008] According to the present invention, the above problem is solved as follows. A vehicle latch device comprising a base member pivotally mounted to a latch that can engage with a striker and a ratchet having an engaging claw portion that prevents the latch from rotating by engaging with an engaging portion provided on the latch, A groove is formed in at least a portion of the engaging pawl portion of the metal ratchet body of the ratchet, along the rotational direction of the ratchet. The ratchet has a synthetic resin molded part integrally molded in which a part of the engaging claw portion is covered with synthetic resin so that a metal surface of the ratchet body is exposed. The synthetic resin molded portion covers the groove and has a buffer portion that protrudes beyond the exposed metal surface of the engaging claw portion and can contact the engaging portion of the latch. The ratchet has at least the groove surface formed with irregularities.

[0009] According to the present invention, the latch reliably contacts the ratchet because the cushioning portion, which is provided on a part of the ratchet's engaging claw, protrudes beyond the exposed metal surface. Furthermore, since the engaging portion of this latch is molded from resin, it slides smoothly against the ratchet, which has a low-friction cushioning portion and an exposed metal surface to which a lubricant is applied. The ratchet's cushioning portion is more firmly fixed to the ratchet body by the close contact between the grooved and recessed areas and the molded resin. This allows the latch to slide smoothly and stably against the ratchet's cushioning portion, enabling stable and smooth operation over a long period. Furthermore, the ratchet's cushioning portion reduces contact noise with the latch, improving the quality of the vehicle latch device over the long term.

[0010] According to another aspect of the present invention, the cushioning portion made of synthetic resin is provided on the side of the end portion of the ratchet that has the engaging claw portion when viewed from the shaft portion of the ratchet, up to a portion slightly below the contact portion between the latch and the ratchet in the groove, and the cushioning portion of the engaging claw portion is continuous with the stress-relieving portion made of synthetic resin provided in the extension of the groove. As a result, the load from the full latch engagement portion is received by the entire stress-relieving portion of the extension of the groove, so that even a shallow groove can withstand the load sufficiently, and the load can be received without making the groove deeper and the buffer portion thicker.

[0011] According to another aspect of the present invention, the groove of the engaging claw is located approximately in the center of the thickness direction of the engaging claw between the pair of exposed metal surfaces of the ratchet body, and the groove is provided in a band shape over its entire length on the side surface of the end of the ratchet on the side having the engaging claw when viewed from the shaft. As a result, the buffer portion fits more firmly into the groove of the engaging claw portion over a long distance, becoming more integrated with the engaging claw portion and securely fixed, allowing the latch device to operate stably over a long period of time.

[0012] According to another aspect of the present invention, the buffer portion is configured such that the molded resin and the uneven portion provided in the groove are in close contact. The metal exposed surface of the engaging claw portion has an uneven surface. As a result, the buffer portion is firmly fixed, allowing the latch device to operate stably over a long period of time. Furthermore, the latch reliably contacts the buffer portion, which is provided on a part of the ratchet's engaging pawl, because the buffer portion protrudes beyond the exposed metal surface. The engaging portion of the latch is molded from resin, so it slides smoothly against the ratchet, which has a low-friction buffer portion and an exposed metal surface to which lubricant is applied. With this configuration, the lubricant applied to the uneven parts of the exposed metal surface is retained by entering the recesses. Therefore, even when the buffer portion and the exposed metal surface become flush due to a load at the engagement position of the latch and ratchet, the lubricant applied to the metal part takes precedence, suppressing deterioration of sliding resistance and allowing the latch device to operate stably over a long period of time.

[0013] According to another aspect of the present invention, the entire end surface of the groove, that is, the end surface including the engaging claw, is shot peened. This provides an uneven surface on the entire end surface of the ratchet on the side with the engaging claw when viewed from the shaft. As a result, compressive residual stress is applied to the grooves and exposed metal surfaces, improving fatigue strength and wear resistance. In addition, the interlocking of the grooves with the molded resin and the ratchet mechanism firmly secure the molded synthetic resin part, allowing the latching device to operate stably over a long period of time.

[0014] According to another aspect of the present invention, the synthetic resin molded portion is configured such that the jaw molded portion, which covers the jaw portion of the ratchet with which the tip of the engaging portion slides when the latch rotates, and the cushioning portion are smoothly connected. This enables smooth rotation of the latch and ratchet when opening and closing the door, prevents the generation of abnormal noises that may occur when the latch engagement part contacts the buffer part while the door is closed, and improves the quality of the vehicle latch device.

[0015] According to another aspect of the present invention, the buffer portion is made of a rigid synthetic resin. This makes it possible to achieve both strength and durability, and slidability with the latch, so that the latch device can operate stably over a long period of time.

[0016] According to another aspect of the present invention, a shaft portion that rotatably supports the ratchet on the base member is formed of resin, and is provided integrally with the synthetic resin molded portion. This makes it possible to reduce the number of components of the latch device and the assembly man-hours, and achieve cost reduction.

[0017] According to another aspect of the present invention, the ratchet has a rust-preventive plating layer applied on the surface. By subjecting this rust-preventive plating layer to shot peening, deep irregularities can be formed, so that compressive residual stress is imparted to the groove portion and the exposed metal surface, improving fatigue strength and wear resistance. Furthermore, the synthetic resin molded portion formed by resin molding can be more firmly fixed to the ratchet, so that the latch device can operate stably over a long period of time. [Brief Description of the Drawings]

[0018] [Figure 1] This is a front view of the latch device according to the first embodiment of the present invention, showing the latch in the door open position state. [Figure 2] This is an enlarged perspective view of the ratchet in the first embodiment of the present invention. [Figure 3] This is a plan view of the ratchet shown in Figure 2. [Figure 4] This is a rear view of the ratchet shown in Figure 2. [Figure 5A] This is a perspective view showing a metallic ratchet main body. [Figure 5B] This is a rear view of the ratchet main body shown in Figure 5A. [Figure 6] This is an explanatory diagram of shot peening performed on the ratchet main body. [Figure 7] This is a vertical cross-sectional view taken along line VII-VII of Figure 3, showing the ratchet in which the synthetic resin molded portion is formed on the surface of the ratchet main body. [Figure 8A] This is a cross-sectional view along line AA in Figure 7. [Figure 8B] Figure 7 shows a cross-sectional view along line BB. [Figure 9] This is a perspective view of a ratchet with a synthetic resin molded part formed on the surface of the ratchet body. [Figure 10] This is an explanatory diagram of the door closing operation in the latch device of the first embodiment. [Figure 11] This is an explanatory diagram of the door closing operation in the latch device of the first embodiment. [Figure 12] This is an explanatory diagram of the door closing operation in the latch device of the first embodiment, showing the fully latched position. [Figure 13A] This diagram illustrates the problems with the latch device described in Patent Document 1. [Figure 13B] This diagram illustrates the problems with the latch device described in Patent Document 1. [Figure 14] This diagram illustrates the operation and effects of a latch device according to the first embodiment of the present invention. [Figure 15A] This is a side view of a ratchet, which is a second embodiment of the present invention, in which the ratchet body and the shaft are integrally formed. [Figure 15B] Figure 15A is a plan view of the ratchet. [Modes for carrying out the invention]

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a front view of a latch device 1 according to a first embodiment of the present invention, showing the latch in the open position of the door. The latch device 1 includes a synthetic resin base member 2 fixed to a door (not shown) that is openable and closable on the vehicle body. Inside the base member 2 is a latch 5 pivotally attached by a pivot 3 and capable of engaging with a striker 4 fixed to the vehicle body, and a ratchet 7 pivotally attached by a pivot 6 that engages with the latch 5 engaged with the striker 4, thereby preventing the latch 5 from rotating in the open direction (clockwise in Figure 1). Note that in Figure 1, the cover plate that covers the surface of the base member 2 is omitted in order to clearly show the internal structure of the latch device 1.

[0020] The latch 5 is made of a metal material such as steel and has an engagement groove 51 that can engage with the striker 4, a half-latch engagement portion 52 that can engage with the engagement claw portion 71 of the ratchet 7, and a full-latch engagement portion 53. As the door closes, the striker 4 engages with the engagement groove 51, causing it to rotate from the open position shown in Figure 1 to the full-latch position shown in Figure 12. A synthetic resin molded portion 8 is integrally molded on the outer circumferential surface of the latch 5, except for the full-latch engagement portion 53 and its vicinity. The latch 5 is normally biased toward the open position by a spring (not shown).

[0021] Figure 2 is an enlarged perspective view of the ratchet 7 of the latching device 1. Figure 3 is a plan view of the ratchet, and Figure 4 is a rear view of the ratchet. The ratchet body 70 is made of a highly rigid metal material, and a synthetic resin molded part 9 is integrally molded on its outer surface. A pivot hole 72 into which the pivot shaft 6 (see Figure 1) is pivotally fitted is provided near the center of the ratchet body 70, and an engaging claw part 71 is provided at the rotating end. The ratchet 7 is constantly biased toward the engagement position with the latch 5 by a spring (not shown), and rotates from the engagement position toward the release direction (clockwise in Figure 1) against the biasing force of the spring, in accordance with the operation of a release lever (not shown) provided on the back side of the base member 2.

[0022] The engaging claw portion 71 engages with the half-latch engaging portion 52 or full-latch engaging portion 53 of the latch 5 when the latch 5 rotates from the open position to the fully latched position, thereby holding the latch 5 in the half-latch or fully latched position. Approximately in the center of the thickness direction of the claw portion 71, a strip-shaped groove portion 10 (see Figures 3 and 4) is provided, extending from the tip 71a of the engaging claw portion 71 along the rotational direction to a predetermined position. The groove 10 is formed on the engaging pawl 71 of the metal ratchet body 70 of the ratchet 7, along the direction of rotation of the ratchet 7.

[0023] The ratchet 7 has a synthetic resin molded part 9 integrally molded with it, which covers a portion of the engaging claw portion 71 with synthetic resin so that the metal surface of the ratchet body 70 is exposed as a pair of exposed metal surfaces 71b. This synthetic resin molded part 9 covers the groove portion 10 and has a buffer portion 91 that protrudes beyond the exposed metal surface 71b of the engaging claw portion 71 and can contact the engaging portion of the latch 5. Furthermore, a side molded part 92 that covers the outer surface of the ratchet 7, an edge molded part 93 that covers the edge of the ratchet 7, and a stress relief part 94 are integrally molded with it. The synthetic resin buffer portion 91 extends from the tip 71a of the engaging claw portion 71 on the side of the end of the ratchet 7 that has the engaging claw portion 71, not only to the area sandwiched between the pair of exposed metal surfaces 71b corresponding to the contact area between the latch 5 and the ratchet 7, but also through a stepped portion 10a (see Figure 2) slightly below this contact area, to a synthetic resin stress relief portion 94 provided on the extension of the groove portion 10. The lower end 94e of this stress relief portion 94 is located at the lowest end of the ratchet 7. The exposed metal surface 71b of the ratchet body 70 is formed as a curved surface to facilitate sliding contact with the latch, but the part of the ratchet body 70 adjacent to the stress relief portion 94 is formed as a flat surface for easier molding. Since the stress relief portion is formed to slightly overlap the curved surface in addition to the flat surface, the synthetic resin molded portion 9 is firmly fixed by the ratchet body 70, allowing for stable operation over a long period of time.

[0024] The entire surface of the end side of the ratchet 7 on the side with the engaging claw portion 71, as viewed from the shaft portion 72, is provided with a surface 75 (see Figure 6) having numerous bumps and grooves. The cushioning portion 91 of the ratchet 7 is more firmly fixed to the ratchet body by the close contact between the surface 75 provided in the groove portion 10 and the molded resin, allowing for stable operation over a long period of time. Furthermore, the cushioning portion 91 of the ratchet 7 can reduce the noise of contact with the latch 5, thereby improving the quality of the vehicle latch device.

[0025] The cushioning portion 91 and stress relief portion 94 are molded to fit into the groove portion 10. The synthetic resin molded portion 9 of the ratchet 7, in particular the cushioning portion 91, is made of hard synthetic resin. By using hard synthetic resin, the cushioning portion 91 can achieve both strength and durability and sliding properties with the latch, allowing it to operate stably over a long period of time.

[0026] The groove 10 is located approximately in the center in the thickness direction of the engaging claw portion 71, which is sandwiched between a pair of exposed metal surfaces 71b of the ratchet body, and the groove 10 is provided in a band shape over its entire length on the side surface of the end of the ratchet 7 that has the engaging claw portion 71, as viewed from the shaft portion. As a result, the cushioning portion 91 fits into the groove of the engaging claw portion 71 over a long distance, becoming more integrated with the engaging claw portion 71 and firmly fixing the cushioning portion 91, allowing it to operate stably over a long period of time.

[0027] The buffer portion 91 protrudes slightly beyond the exposed metal surface 71b and is capable of contacting the full latch engagement portion 53 and the half latch engagement portion 52. It is molded to smoothly connect from the groove portion 10 provided at the tip 71a of the engagement claw portion 71 to the edge molding portion 93 formed on the jaw portion 73 at the edge of the ratchet 7. Furthermore, since exposed metal surfaces 71b are formed on both sides of the buffer portion 91 in the thickness direction, the buffer portion 91 is molded so as not to connect directly to the side molding portion 92.

[0028] Next, the manufacturing method of the ratchet 7 in this embodiment will be explained with reference to Figures 5A to 9. First, as shown in Figures 5A and 5B, the ratchet body 70 is formed, for example, by punching out a steel plate using fine blanking, and then machining the punched-out part to form the groove 10. The groove 10 is formed in the center of the engaging claw portion 71 on the end side of the ratchet body 70, along the direction of rotation of the ratchet, and a pair of exposed metal surfaces 71b are formed on both sides thereof.

[0029] Next, as shown in Figure 6, a rust-preventive plating layer 76 is applied to the surface of the end side of the ratchet body 70. Furthermore, shot peening is performed on the surface of the end side surface to which this anti-corrosion plating layer 76 is applied, forming an uneven surface 75 with numerous irregularities. Shot peening is a process in which countless small spheres are impacted at high speed onto the metal surface of the end side surface, thereby causing work hardening through plastic deformation and imparting compressive residual stress to the metal surface. As a result of this process, compressive residual stress is imparted to the groove 10 and the exposed metal surface 71b, improving fatigue strength and wear resistance.

[0030] Next, the synthetic resin molded part 9 that covers the ratchet body 70 is molded integrally with the ratchet body 70 by insert molding. That is, in insert molding, the ratchet body 70 is inserted into an injection molding die, and then a material such as synthetic resin is injected to form the synthetic resin molded part 9. During insert molding, care is taken to prevent resin from being supplied to the exposed metal surface 71b. The surface of the end side of the ratchet body 70 has numerous irregularities formed on it by shot peening. The depth of the irregularities is, for example, a maximum of 15 μm from the top to the bottom of each irregularity. As a result, compressive residual stress is applied to the grooves 10 and the exposed metal surface, improving fatigue strength and wear resistance.

[0031] Through these processes, the ratchet 7 is completed as shown in Figures 7 to 9. Figure 7 shows the ratchet 7 with the synthetic resin molded part 9 formed on the surface of the ratchet body 70, and is a longitudinal cross-sectional view along line VII-VII in Figure 3. Figure 8A is a cross-sectional view along line AA in Figure 7, and Figure 8B is a cross-sectional view along line BB in Figure 7. The depth D1 of the groove 10 is, for example, in the range of 1 mm to 2 mm. For example, when the depth D1 of the groove 10 is 1 mm, the thickness D2 of the stress relaxation portion 94 is about 1.8 mm, and the protrusion height H of the buffer portion 91 from the exposed metal surface 71b is, for example, 0.1 mm. In this embodiment, the latch 5 reliably contacts the ratchet 7 because the buffer portion 91, which is provided on a part of the engaging claw portion 71 of the ratchet 7, protrudes slightly beyond the exposed metal surface 71b. Furthermore, since the engaging portion of the latch 5 is molded from resin, it slides smoothly against the ratchet 7, which has a low-friction buffer portion 91 and an exposed metal surface to which a lubricant is applied.

[0032] Since the load from the full latch engagement portion 53 is received by the entire stress-relieving portion of the groove extension, a shallow groove is sufficient, and the load can be received without making the groove deeper and increasing the thickness of the buffer portion 91. Furthermore, because the buffer portion 91 fits into the groove portion 10 of the engagement claw portion 71 over a long distance, it integrates more firmly with the engagement claw portion 71, allowing the buffer portion 91 to be securely fixed and operate stably over a long period of time.

[0033] In this embodiment, on the side of the end portion of the ratchet 7 that has the engaging claw portion 71 when viewed from the shaft portion, a cushioning portion 91 made of synthetic resin is provided up to a stepped portion 10a slightly below the contact portion between the latch 5 of the groove portion 10 and the ratchet 7, and the cushioning portion of the engaging claw portion 71 is further continuous with a stress-relieving portion made of synthetic resin provided in the extension of the groove portion 10. As a result, the load P from the full latch engagement portion 53 is received by the entire stress-relieving portion of the groove extension, so a shallow groove is sufficient, and the load can be received without making the groove deeper and increasing the thickness of the buffer portion (see Figure 14).

[0034] In this embodiment, the buffer portion 91 is configured such that the molded resin and the uneven portion 75 provided in the groove portion 10 are in close contact. The metal exposed surface 71b of the engaging claw portion 71 has the uneven portion 75 on its surface. As a result, the buffer portion 91 is firmly fixed and can operate stably over a long period of time. Furthermore, the latch 5 reliably contacts the buffer portion 91 provided on a part of the engaging claw portion 71 of the ratchet 7 because this buffer portion protrudes more than the metal exposed surface 71b. Since the engaging portion of the latch 5 is molded from resin, it is configured to slide smoothly against the ratchet 7, which has a low-friction buffer portion and a metal exposed surface to which lubricant is applied. With this configuration, the lubricant applied to the uneven portion 75 of the exposed metal surface 71b is retained by filling into the recesses. Therefore, even when the buffer portion 91 and the exposed metal surface 71b become flush due to a load at the position where the latch 5 and the ratchet 7 engage, the lubricant applied to the metal portion becomes more dominant in its action, suppressing deterioration of sliding resistance and allowing the latch device to operate stably over a long period of time.

[0035] Furthermore, Figure 9 is a perspective view of a ratchet 7 with a synthetic resin molded portion 9 formed on the surface of the ratchet body. According to this embodiment, the synthetic resin molded portion 9 is configured such that the jaw molded portion, which covers the jaw portion 73 of the ratchet 7 that the tip of the engaging portion slides against when the latch 5 rotates, and the buffer portion 91 are smoothly connected. This enables smooth rotation of the latch 5 and ratchet 7 when opening and closing the door, prevents the generation of abnormal noise that may occur when the engaging portion of the latch 5 comes into contact with the buffer portion 91 while the door is closed, and improves the quality of the vehicle latch device.

[0036] Next, the operation of the embodiment according to the present invention will be described with reference to Figures 1, 10 to 12. When the door is closed, the striker 4 engages with the engagement groove 51 of the latch 5, and the latch 5 rotates from the open position in Figure 1 to the fully latched position against the biasing force of the spring. As the ratchet 7 moves in the process of the latch 5 reaching the fully latched position, the ratchet 7 rotates in the release direction as the tip of the full latch engagement portion 53 slides in contact with the edge molding portion 93 that covers the jaw portion 73 of the ratchet 7, following the half latch engagement portion 52, as shown in the first state in Figure 10. Furthermore, as the latch 5 rotates toward the full latch position, the ratchet 7, as shown in the second state in Figure 11, has the tip 71a of the engaging claw 71 in contact with the outer edge of the full latch engaging portion 53. When the latch 5 rotates further and reaches the overstroke position, the ratchet 7 rotates toward the engaging position, and then the latch 5 returns from the overstroke position to the full latch position due to the door's sealing reaction force. As shown in the third state in Figure 12, the engaging claw 71 engages with the full latch engaging portion 53, and the latch 5 is held in the full latch position.

[0037] In the first state described above, the buffer portion 91 is molded to smoothly connect from the groove portion 10 to the edge-molded portion 93, so that the outer edge of the full latch engagement portion 53 can smoothly slide against the jaw portion 73 of the ratchet 7. This enables smooth rotation of the latch 5 and the ratchet 7, preventing the generation of abnormal noise during the door closing operation. In the second state described above, the buffer portion 91 provided at the tip 71a of the engaging pawl portion 71 of the ratchet 7 comes into contact with the outer edge of the full-latch engaging portion 53, thereby reducing the contact noise.

[0038] In the third state described above, the buffer portion 91 comes into contact with the full latch engagement portion 53 of the latch 5, thereby mitigating the contact noise. When a large load is applied to the engagement claw portion 71, the buffer portion 91 that is in contact with the full latch engagement portion 53 elastically deforms, causing the full latch engagement portion 53 to come into contact with the exposed metal surface 71b of the engagement claw portion 71, thereby ensuring the meshing strength between the full latch engagement portion 53 and the engagement claw portion 71. Since the cushioning portion 91 is molded to fit into the groove portion 10 of the engaging claw portion 71, the fixation of the cushioning portion 91 to the engaging claw portion 71 is strengthened, improving durability against repeated loads by the full latch engaging portion 53. Furthermore, since the entire area in the plate thickness direction, including the stepped portion 10a, on the stepped portion 10a side of the groove portion 10 of the engaging claw portion 71 is covered by the edge molding portion 93a, the cushioning portion 91 can be fixed to the engaging claw portion 71 more firmly. This improves durability against repeated loads by the full latch engaging portion 53.

[0039] Next, a second embodiment of the present invention will be described. Figure 15A is a side view of a ratchet according to the second embodiment, and Figure 15B is a top view of the ratchet of Figure 15A. In this embodiment, the ratchet 7 and the shaft portion 6 that rotatably supports the ratchet on the base member 2 are molded to be integrally formed from resin. That is, the synthetic resin molded portion 9 surrounding the ratchet body 70 of the ratchet 7 and the shaft portion 6 are molded to be integrally formed from resin, preferably a hard synthetic resin. This reduces the number of parts and assembly time, thereby lowering the cost of the ratchet. [Explanation of symbols]

[0040] 1. Latching device 2 Base member 3 Axis 4 Striker 5 Latch 51 Engagement groove 52 Half-latch engagement portion 53 Full latch engagement section 6 Axis 7 Ratchet 70 Ratchet Body 71 Engaging claw portion 71a Tip 71b Exposed metal surface 72 Pivot hole 73. Jaw 75 Uneven part 76 Anti-corrosion plating layer 8. Synthetic resin molding section 9. Synthetic resin molding section 91 Buffer section 92 Side molding part 93 Edge molding section 93a Edge molding section 94 Stress relaxation section 94e Stress relaxation end 10 grooves 10a Stepped section

Claims

1. A vehicle latch device comprising a base member pivotally mounted to a latch that can engage with a striker and a ratchet having an engaging claw portion that prevents the latch from rotating by engaging with an engaging portion provided on the latch, A groove is formed in at least a portion of the engaging pawl portion of the metal ratchet body of the ratchet, along the rotational direction of the ratchet. The ratchet has a synthetic resin molded part integrally molded, in which a part of the engaging claw portion is covered with synthetic resin so that the metal surface of the ratchet body is exposed. The synthetic resin molded portion covers the groove and has a buffer portion that protrudes beyond the exposed metal surface of the engaging claw portion and can contact the engaging portion of the latch. The ratchet is a vehicle latching device characterized in that at least the surface of the groove portion has irregularities formed on it.

2. The groove is located approximately in the center in the thickness direction of the engaging claw portion sandwiched between the pair of exposed metal surfaces of the ratchet body. The vehicle latch device according to claim 1, characterized in that the groove portion is provided in a band shape over its entire length on the side surface of the end portion of the ratchet that has the engaging claw portion, as viewed from the shaft portion of the ratchet.

3. The vehicle latch device according to claim 2, characterized in that the buffer portion made of synthetic resin is provided on the end side surface to a portion slightly below the contact portion between the latch and the ratchet in the groove, and the buffer portion of the engaging claw portion is continuous with the stress relief portion made of synthetic resin provided in the extension of the groove.

4. The vehicle latch device according to claim 1, characterized in that the uneven surface is provided on the entire surface of the end side of the ratchet that has the engaging claw when viewed from the shaft of the ratchet.

5. The vehicle latch device according to claim 1 or 2, characterized in that the synthetic resin molded portion has a jaw molded portion that covers the jaw portion of the ratchet with which the tip of the engaging portion slides when the latch rotates, and the cushioning portion are smoothly connected.

6. The vehicle latch device according to claim 1, characterized in that the buffer portion is made of a hard synthetic resin.

7. The vehicle latch device according to claim 6, characterized in that the shaft portion that rotatably supports the ratchet on the base member is molded from resin and provided integrally with the synthetic resin molded portion.

8. In a method for manufacturing a vehicle latch device, the base member is pivotally mounted with a latch that can engage with a striker and a ratchet having an engaging claw portion that prevents the latch from rotating by engaging with an engaging portion provided on the latch, A process for manufacturing a metal ratchet body, comprising the step of forming a groove on the side surface of the end of the ratchet that has the engaging claw portion when viewed from the shaft portion of the ratchet, along the direction of rotation of the ratchet; The process of applying shot peening to the surface of the end side of the ratchet body to form an uneven surface at least on the surface of the groove, A method for manufacturing a vehicle latch device, comprising the step of integrally molding a synthetic resin molded part to the ratchet body, wherein a resin mold is applied to the engaging claw portion, a part of the engaging claw portion is made into a metal exposed surface that exposes the metal surface of the ratchet body, and the other part of the engaging claw portion is made into a buffer portion that covers the uneven portion and protrudes more than the metal exposed surface and can contact the engaging portion of the latch.

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