JP2016169718A - Gear pump, or motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear pump or a motor comprising: gears for meshing each other while making a pair; shafts for bearing those gears individually; and a casing having a gear storage chamber for storing said gears, in which a lubrication between the gear or shaft and the casing can be effected with a small number of parts by introducing no special facility in manufacturing.SOLUTION: The side face of at least one of pairing gears and a casing are brought into direct sliding contact thereby to provide a recess formed by a shot-blasting, in a slide contact face of said casing with said gear.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gear pump or a motor that feeds hydraulic fluid by using tooth spaces of a driving gear and a driven gear that form a meshing gear pair with each other.

  2. Description of the Related Art Conventionally, in a gear pump or motor comprising a pair of gears, shafts that respectively support the gears, and a casing that houses at least a part of the entire pair of gears and the shafts, The following is known as a configuration for suppressing the amount of hydraulic fluid leakage. As shown in FIG. 4, a driving gear A2 and a driven gear A3, which are paired gears, are arranged in a gear housing chamber A11a of the casing A1, and side surfaces A2a, A3a, A2b of the gears A2, A3 are arranged. A side plate A6 is arranged on A3b, and a gasket A8 is mounted on a surface A6b opposite to the gears A2 and A3 of the side plate A6. The drive shaft A4 that supports the drive gear A2 and the driven shaft A5 that supports the driven gear A3 are inserted through the bearing holes A11x, A11y, A12x, A12y, and the drive shaft A4 and the bearing holes A11x, A12x A bush A7 is interposed between the driven shaft A5 and the bearing holes A11y and A12y. After that, the hydraulic fluid from the high pressure side is guided to the space defined by the gasket A8 and the inner wall of the gear housing chamber A11a of the casing A1, so that the side plate A6 has side surfaces A2a, A3a, A2b, A3b of the gears A2, A3. Lightly pressed toward As another example, as shown in FIG. 5, a side plate B6 disposed on one side B2a, B3a side of the gears B2, B3 is fitted with a gasket B8, while the other side surface B2b of the gears B2, B3. The side plate B9 disposed on the B3b side is not provided with a gasket, and the gap between the side plate B9 and the gears B2, B3 and the casing B1 is reduced, and the side plate B9 is provided in the casing B1 to accommodate the shafts B4, B5. Of the shaft holes B11x and B11y that are formed on the side where the gasket B8 is not provided, those that do not open to the outside of the casing B1 are also known. The side plate used in such a gear pump or motor is made of a material that reduces the coefficient of friction with the side surface of the gear. Of the parts of the gear pump shown in FIG. 5, those corresponding to those in the gear pump shown in FIG.

  By the way, for the purpose of cost reduction by reducing the number of parts, it is considered that at least one side plate is omitted as shown in FIG. That is, a configuration in which one side surface C2a, C3a of the gears C2, C3 is in direct sliding contact with the casing C1 is considered. Of the parts of the gear pump shown in FIG. 6, those corresponding to those in the gear pump shown in FIG.

  However, when the side plate is omitted, the following problems may occur. That is, when the side plate is omitted and the side surfaces C2a and C3a of the gears C2 and C3 are directly slidably contacted with the casing C1, the friction coefficient between the side surfaces C2a and C3a of the gears C2 and C3 and the casing C1 is provided with the side plate. In this case, the friction coefficient between the side surfaces C2a and C3a of the gears C2 and C3 and the side plate is larger. Then, the output of a motor or the like for rotating the gears C2 and C3 at a desired number of rotations becomes larger than when a side plate is provided, and there is a problem that mechanical efficiency is lowered. Further, since heat generated by friction between the side surfaces C2a and C3a of the gears C2 and C3 and the casing C1 increases, the gears C2 and C3 and the casing C1 are deteriorated by heat, and there is a problem that durability is lowered. To do.

  On the other hand, conventionally, a structure in which a bush is interposed between a shaft that supports the gear and a bearing hole provided in the casing to support the shaft is employed. The bush used for such a gear pump or motor is also made of a material that reduces the coefficient of friction with the shaft. However, the bush may be omitted for the purpose of reducing the cost by reducing the number of parts. It is considered.

  However, even when the bush is omitted, the same problem as when the above-described side plate is omitted may occur.

  As one of the methods for solving the above-described problems, a recess is provided on the outer surface of the shaft or the surface that is in sliding contact with the side surface of the gear of the casing, and lubrication is achieved by storing a working fluid in the recess. Known (see, for example, Patent Documents 1 and 2).

  However, when the method described in the preceding stage is adopted, there is another problem that a facility for providing a concave portion on the outer surface of the shaft or the surface that is in sliding contact with the side surface of the gear of the casing is separately required.

JP 2005-42627 A JP 2007-263019 A

  The present invention pays attention to the above points, and realizes a configuration capable of achieving lubrication between a gear or a shaft and a casing with a small number of parts and without introducing special equipment for manufacturing. Objective.

  In order to solve the above problems, the gear pump or motor of the invention according to the present application has the following configuration.

  That is, the gear pump or motor according to the invention of claim 1 includes a pair of gears that mesh with each other, a shaft that supports each of these gears, and a casing that has a gear housing chamber for housing the gears. A gear pump or a motor, wherein at least one side surface of the pair of gears and the casing are in direct sliding contact, and a concave portion formed by shot blasting is formed on the sliding contact surface of the casing with the gear. Is provided.

  According to a second aspect of the present invention, there is provided a gear pump or a motor, wherein a pair of gears that mesh with each other, a shaft that supports each of the gears, a gear storage chamber for storing the gear, and the shaft are rotatable. A gear pump or a motor including a casing having a bearing hole for supporting the shaft, wherein at least one of the shafts and the bearing hole of the casing are in direct sliding contact, and the shaft of the bearing hole A recess formed by shot blasting is provided on the sliding contact surface.

  According to these configurations, lubrication between the casing and the gear or between the bearing hole and the shaft can be achieved by guiding the hydraulic fluid into the recess. Therefore, it is possible to improve mechanical efficiency and durability while reducing the number of parts. In addition, the casing of this type of gear pump is often formed by die casting or casting using a sand mold, and shot blasting is performed for the purpose of removing burrs and burrs generated during processing. The above-mentioned effect can be obtained by forming the recess by applying shot blast to the sliding contact surface with the gear or the bearing hole without preparing special equipment for providing the recess on the sliding contact surface or the bearing hole. it can.

  As an aspect in which the above effects can be suitably obtained, the casing is formed by casting using a mold. In the present invention, "casting using a mold" refers to die casting, casting using a sand mold, or the like, injecting molten metal into the mold, and taking out the metal after it has cooled and solidified inside the mold. It is a concept showing general molding by casting.

  According to the present invention, it is possible to realize a configuration capable of achieving lubrication between a gear or shaft and a casing with a small number of parts and without introducing special equipment for manufacturing.

Schematic which shows the gear pump which concerns on one Embodiment of this invention. The enlarged view of the area | region X in FIG. The enlarged view of the area | region Y in FIG. Schematic which shows the conventional gear pump. Schematic which shows the conventional gear pump. Schematic which shows the conventional gear pump.

  An embodiment of the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, the gear pump according to the present embodiment mainly includes a casing 1 formed by joining a body 11 having a gear housing chamber 11a therein and a cover 12 that closes the gear housing chamber 11a of the body 11. The external gear pair housed and held in the gear housing chamber 11 a of the casing 1, that is, the driving gear 2 and the driven gear 3, and the driving shaft 4 and the driven shaft that support the driving gear 2 and the driven gear 3. 5 and a side plate 6 that is in contact with one of the side surfaces 2a and 3a of the drive gear 2 and the driven gear 3.

  The drive gear 2 and the driven gear 3 are well-known ones in which a plurality of tooth bodies are provided at predetermined intervals along the outer peripheral surface. In the present embodiment, the drive shaft 4 is integrally extended from the center of the drive gear 2 in the rotational axis direction, and the driven shaft 5 is integrally extended from the driven gear 3 in the rotational axis direction. However, the drive gear 2 and the drive shaft 4 may be configured separately, and the driven gear 3 and the driven shaft 5 may be configured separately.

  The casing 1 is formed by joining a body 11 and a cover 12 by a fastening tool (not shown) (for example, a bolt).

  As shown in FIG. 1, the body 11 has a gear housing chamber 11a for housing the drive gear 2 and the driven gear 3, a high-pressure side port (not shown) communicating with the gear housing chamber 11a, and a gear. A low-pressure side port (not shown) communicating with the storage chamber 11a and shaft holes 11x and 11y for inserting the drive shaft 4 and the driven shaft 5 respectively are formed. The front surface 11 f of the body 11 faces the cover 12.

  As shown in FIGS. 3 and 4, the cover 12 is provided with shaft holes 12 x and 12 y through which the drive shaft 2 and the driven shaft 3 are inserted. Further, the rear surface 12 r of the cover 12 faces the body 11.

  As shown in FIG. 1, the side plate 6 is disposed at one position so as to be brought into contact with one of the side surfaces 2 a and 3 a of the drive gear 2 and the driven gear 3, and one side surface 2 a of the drive gear 2 and the driven gear 3. It is for sealing 3a. Here, in the sliding surface 6 a side of the side plate 6, a state in which high-pressure hydraulic fluid is introduced into the high-pressure side region from the discharge port and the driving gear 2, the driven gear 3 and the movable side plate 6 are housed in the casing 1. Thus, a seal portion capable of introducing a high-pressure fluid is formed between the non-sliding surface 6 b of the movable side plate 6 and the casing 1. Further, the side plate 6 is provided with a shaft hole 6c for allowing the drive shaft 4 or the driven shaft 5 to pass therethrough.

  The gasket 8 is made of an elastic material. The gasket 8 is mounted in a state of being in contact with a gasket mounting protrusion (not shown) provided on the non-sliding surface 6b of the side plate 6, and is pressure-bonded to the non-sliding surface 6b and the casing 1. The section is divided into a low pressure side, that is, a suction port side, and a high pressure side, that is, a discharge port side.

  Therefore, in this embodiment, as shown in FIGS. 1 and 2, the body 11 is in direct sliding contact with the other side surfaces 2 b and 3 b of the drive gear 2 and the driven gear 3. In addition, a large number of recesses 11 z are formed on the sliding contact surface 11 c of the body 11 with respect to the drive gear 2 and the driven gear 3.

  The recesses 11z are formed by shot blasting and are randomly arranged. Such shot blasting is a processing method usually used in the surface finishing process of the casing formed by die casting or casting, and the recess 11z is also formed in this process, so that the processing can be performed efficiently. it can.

  In this embodiment, as shown in FIGS. 1 and 3, bushes are interposed between the drive shaft 4 and the bearing holes 11x and 12x and between the driven shaft 5 and the bearing holes 11y and 12y. They are in direct sliding contact. In addition, a large number of recesses 11z, 12z are also formed in the bearing holes 11x, 11y, 12x, 12y by shot blasting.

  The recesses 11z and 12z are formed by performing a shot blasting process for manufacturing the body 11 and the cover 12 also on the sliding contact surface 11c with the gear and the bearing holes 11x, 11y, 12x and 12y.

  During operation of this gear pump, most of the hydraulic fluid is introduced into the tooth gap from the low pressure port and is guided to the high pressure port as the gears 2 and 3 rotate. On the other hand, a part of the hydraulic fluid is guided to the non-sliding surface 6b side of the side plate 6 from one side surface side of the gear. The other part of the hydraulic fluid reaches the sliding surface 11c and the shaft holes 11x and 11y while flowing along the side surfaces 2b and 3b on the side where the side plate 6 of the gears 2 and 3 is not provided. It remains in the recess 11z formed in the surface 11c and the shaft holes 11x and 11y. Then, lubrication and cooling between the gears 2 and 3 or the shafts 4 and 5 and the body 11 are performed by the hydraulic fluid remaining in the recess 11z. Further, another part of the hydraulic fluid reaches the shaft holes 12x and 12y and stays in the recesses 12z formed in the shaft holes 12x and 12y. Then, lubrication and cooling between the shafts 4 and 5 and the body 11 are performed by the hydraulic fluid remaining in the recess 12z.

  As described above, according to the configuration of the present embodiment, the hydraulic fluid is guided into the recess 11z, so that the gap between the sliding surface 11c of the body 11 constituting the casing 1 and the gears 2 and 3 is achieved. , And the bearing holes 11x and 11y and the shafts 4 and 5 can be lubricated. Therefore, it is possible to improve mechanical efficiency and durability while reducing the number of parts.

  And since the said recessed part 11z is formed by performing the shot blasting process at the time of manufacturing the body 11 by die-casting also with respect to the said sliding contact surface 11c and the bearing holes 11x and 11y, special equipment is provided. The above-described effects can be obtained by forming the recess 11z without preparing.

  The present invention is not limited to the embodiment described above.

  For example, in the above-described embodiment, the shaft and the bearing hole are in direct sliding contact, but a bush is provided between one or both of the shaft and the bearing hole of the body and between the shaft and the bearing hole of the cover. It may be interposed.

  In the above-described embodiment, the side plate is attached only to the front side surface of the gear. However, the side plate may be attached only to the rear side surface of the gear. Of course, a concave portion formed by a shot blasting process may be provided on the contact surface with the gear.

  Furthermore, the present invention may be applied not only to a casing formed by die casting, but also to a casing formed by casting using a sand mold. Furthermore, the present invention may be applied to a casing formed by another casting method using a mold. That is, the shot blasting process after the body or cover is taken out of the mold may be applied to the gear sliding contact surface or shaft hole of the body or cover to form a recess where the working fluid can stay.

  In addition, the above-described embodiment includes a casing formed by joining a body having a gear housing chamber that opens in only one direction and a cover that covers the opening of the body. The present invention may be applied to a gear pump or a motor including That is, a rotational driving force is applied to a body having a gear storage chamber that opens on both sides in the extending direction of the shaft that supports the gear, and one opening of the gear storage chamber, specifically, a drive shaft that supports the drive gear among the openings. A casing formed by joining a front cover, which is a cover covering one opening toward the drive source side (front side), and a rear cover, which is a cover covering the other opening of the gear storage chamber. The present invention may be applied to a gear pump or a motor provided. In this case, a side plate between the gear and one of the front cover and the rear cover may be omitted, and a concave portion formed by shot blasting may be formed on the sliding contact surface of the cover on the side where the side plate is omitted. Of course, in the gear pump or motor having such a configuration, a concave portion formed by shot blasting may be formed on a sliding contact surface with the shaft of the bearing hole provided in the cover on the side where the side plate is omitted.

  In addition, various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Casing 11a ... Gear storage chamber 11c ... Sliding surface 11x, 11y, 12x, 12y ... Shaft hole 11z, 12z ... Recessed part 2, 3 ... Gear 4, 5, 5 ... Shaft

Claims (3)

A gear pump or motor comprising a pair of gears that mesh with each other, shafts that respectively support these gears, and a casing that has a gear storage chamber for storing the gears,
A gear pump or motor in which at least one side surface of the pair of gears is in direct sliding contact with the casing, and a concave portion formed by shot blasting is provided on the sliding contact surface of the casing with the gear. A pair of gears that mesh with each other, shafts that respectively support these gears, a gear housing chamber that houses the gears, and a casing that has a bearing hole for rotatably supporting the shafts. A gear pump or motor,
A gear pump or motor in which at least one of the shafts and the bearing hole of the casing are in direct sliding contact, and a recess formed by shot blasting is provided on the sliding contact surface of the bearing hole with the shaft. . The gear pump or motor according to claim 1 or 2, wherein the casing is formed by casting using a mold.

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