理解库存的不同类型非常重要，因为库存的分类会影响库存管理的**。持有库存主要是为了**需求，库存可分为周转(基本)库存、安全(缓冲)库存、管道(在途)库存、投机库存。下面将分别对各类库存进行解释。

Understanding the different types of inventory is very important, because the classification of inventory affects the way the inventory is managed.Holding inventory is mainly to meet demand, inventory can be divided into turnover (basic) inventory, safety (buffer) inventory, pipeline (on) inventory, speculative inventory.Each type of inventory will be explained separately below.

周转库存(cycle stock)或基本库存(safe stock)是指在一个订货周期**中**正常需求所需的库存。鸡蛋的例子，1打(12枚)鸡蛋代表周转库存:我们每天食用1枚鸡蛋，每12天购买1次鸡蛋。订货周期不断缩短，意味着相关的周转库存水平也不断**。

Working stock (cycle stock) or basic stock (safe stock) is the inventory required to meet normal demand during an order cycle.For example of eggs, 1 dozen (12) eggs represent working stock: we eat 1 egg a day and buy them once every 12 days.The shortened order cycle, means that the relevant working inventory level is also decreasing.

安全库存(safety stock)或缓冲库存(buffer stock)是指除周转库存外，为应对需求或提前期的不确定性而持有的库存。例如，你偶尔决定用3枚鸡蛋做一次煎蛋卷，而不是每天吃1枚鸡蛋，此时就产生了需求的不确定性。有时，你可能不是12天而是14天才买一次鸡蛋，这就是提前期不确定性的例子。在这两种情况下，你就需要额外的一些鸡蛋以确保鸡蛋不会断档。

Safety stock (safety stock) or buffered stock (buffer stock) is an inventory held in response to demand or uncertainty in advance periods.For example, you occasionally decide to make an omelet once with three eggs instead of eating one egg a day, creating uncertainty in demand.Sometimes, you may not buy 12 days but 14 days, which is an example of early time uncertainty.In both cases, you need some extra eggs to make sure they aren't out of gear.

管道库存(pipeline stock)或在途库存(in-transit stock) 是指处于物流系统不同固定设施(如工厂、仓库或商店)之间的运输途中的库存。在鸡蛋的例子中，指在养鸡场与食品批发商的配送中心之间，或零售店与你的厨房之间运输中的鸡蛋。

Pipeline inventory (pipeline stock) or in-transit inventory (in-transit stock) is an inventory in transit between different fixed facilities (e. g., factories, warehouses, or stores) of the logistics systems.In the case of eggs, eggs transported between a chicken farm and a food wholesaler's distribution center, or between a retail store and your kitchen.

投机库存(speculative stock) 是指为诸如季节性需求、预计价格上涨和潜在产品短缺等原因而持有的库存。举例来说，在复活节有吃炸蛋卷和彩蛋的习俗，因此在复活节假期之前对鸡蛋的需求会大幅**。

Speculative stocks (speculative stock) are stocks held for reasons such as seasonal demand, projected price increases, and potential product shortages.For example, there is a custom of eating fried egg rolls and Easter eggs on Easter, so the demand for eggs increases substantially before the Easter holiday.

尽管持有库存通常是为了**需求，但在某些情况下持有库存是为了**需求，也称为精神库存(psychic stock)。这种类型的库存与零售店有关，其基本思想是消费者看到库存会**其购买。叫这个观点部分解释了一些零售商之所以大量储存某些商品的原因。

Although inventory is usually held to meet demand, inventory in some cases is held to stimulate demand, also known as mental inventory (psychic stock).This type of inventory is related to retail stores, and the basic idea is that consumers see that inventory will spur its purchases.Call this point partly explains why some retailers store certain goods in bulk.